diff --git a/pkgs/development/libraries/qt-5/5.15/default.nix b/pkgs/development/libraries/qt-5/5.15/default.nix
index 863684149df25..467dda6b529a7 100644
--- a/pkgs/development/libraries/qt-5/5.15/default.nix
+++ b/pkgs/development/libraries/qt-5/5.15/default.nix
@@ -10,25 +10,15 @@
   generateSplicesForMkScope,
   lib,
   stdenv,
-  gcc14Stdenv,
   fetchurl,
   fetchgit,
   fetchpatch,
   fetchFromGitHub,
   makeSetupHook,
-  makeWrapper,
-  bison,
-  cups ? null,
-  harfbuzz,
-  libGL,
-  perl,
   python3,
-  gstreamer,
-  gst-plugins-base,
-  gtk3,
-  dconf,
   llvmPackages_19,
   darwin,
+  buildPackages,
 
   # options
   developerBuild ? false,
@@ -59,6 +49,11 @@ let
         url = "https://gitlab.alpinelinux.org/alpine/aports/-/raw/81b14ae4eed038662b53cd20786fd5e0816279ec/community/qt5-qtbase/loongarch64.patch";
         hash = "sha256-BnpejF6/L73kVVts0R0/OMbVN8G4DXVFwBMJPLU9QbE=";
       })
+      (fetchpatch {
+        url = "https://salsa.debian.org/qt-kde-team/qt/qtbase/-/raw/6910758e1141f8ea65a8f2359ac30163d65bf6e2/debian/patches/cross_build_mysql.diff";
+        hash = "sha256-tzmmLmMXmeDwRVjdpWekDJvSkrIIlslC12HP7XPcm3E=";
+      })
+      ./qtbase.patch.d/0015-qtbase-cross-build.patch
     ];
     qtdeclarative = [
       ./qtdeclarative.patch
@@ -66,6 +61,8 @@ let
       ./qtdeclarative-default-disable-qmlcache.patch
       # add version specific QML import path
       ./qtdeclarative-qml-paths.patch
+      ./qtdeclarative-gcc15.patch
+      ./qtdeclarative-cross-build.patch
     ];
     qtlocation = lib.optionals stdenv.cc.isClang [
       # Fix build with Clang 16
@@ -201,6 +198,7 @@ let
       # See: https://bugreports.qt.io/browse/QTBUG-124375
       # Backport of: https://code.qt.io/cgit/qt/qtwebengine-chromium.git/commit/?id=a766045f65f934df3b5f1aa63bc86fbb3e003a09
       ./qtwebengine-ninja-1.12.patch
+      ./qtwebengine-cross-build.patch
     ]
     ++ lib.optionals stdenv.hostPlatform.isDarwin [
       ./qtwebengine-darwin-no-platform-check.patch
@@ -236,35 +234,48 @@ let
       ./qtwebkit.patch
       ./qtwebkit-icu68.patch
       ./qtwebkit-cstdint.patch
+      (fetchpatch {
+        url = "https://src.fedoraproject.org/rpms/qt5-qtwebkit/raw/84f3c61c46bce99bfbd70d8c202e022d62f2ea9a/f/qtwebkit-icu76.patch";
+        sha256 = "sha256-Z+ot7R5Dy+F08FbcXzN4MB2ttxLg0I0P8uVErpbFiu4=";
+      })
+      (fetchpatch {
+        url = "https://src.fedoraproject.org/rpms/qt5-qtwebkit/raw/84f3c61c46bce99bfbd70d8c202e022d62f2ea9a/f/webkit-offlineasm-warnings-ruby27.patch";
+        sha256 = "sha256-g+qkAJD78lPdZzZZ910SZqk0yJlJIBZh9ue4ClRD5L4=";
+      })
+      (fetchpatch {
+        url = "https://src.fedoraproject.org/rpms/qt5-qtwebkit/raw/84f3c61c46bce99bfbd70d8c202e022d62f2ea9a/f/qtwebkit-fix-build-gcc14.patch";
+        sha256 = "sha256-K7TgGux34dMN0Mnm4EsJhNKLdy1VdKTAE3HGRD8KARU=";
+      })
     ]
     ++ lib.optionals stdenv.hostPlatform.isDarwin [
       ./qtwebkit-darwin-no-readline.patch
       ./qtwebkit-darwin-no-qos-classes.patch
     ];
-    qttools = [ ./qttools.patch ];
+    qttools = [
+      ./qttools.patch
+      ./qttools-cross-build.patch
+    ];
   };
 
   addPackages =
     self:
     let
-      qtModuleWithStdenv =
-        stdenv:
-        callPackage ../qtModule.nix {
-          inherit patches;
-          # Use a variant of mkDerivation that does not include wrapQtApplications
-          # to avoid cyclic dependencies between Qt modules.
-          mkDerivation = (callPackage ../mkDerivation.nix { wrapQtAppsHook = null; }) stdenv.mkDerivation;
-        };
-      qtModule = qtModuleWithStdenv stdenv;
+      qtModule = callPackage ../qtModule.nix {
+        inherit patches;
+        # Use a variant of mkDerivation that does not include wrapQtApplications
+        # to avoid cyclic dependencies between Qt modules.
+        mkDerivation = (callPackage ../mkDerivation.nix { wrapQtAppsHook = null; }) stdenv.mkDerivation;
+      };
 
-      callPackage = self.newScope {
-        inherit
-          qtCompatVersion
-          qtModule
-          srcs
-          stdenv
-          ;
+      qtbase-bootstrap = buildPackages.qt5.qtbase.override { bootstrapBuild = true; };
+      # qtbase won't be spliced here, but that's fine as it's only a buildInput
+      qttools-bootstrap = buildPackages.qt5.qttools.override {
+        qtbase = qtbase-bootstrap;
+        qtdeclarative = null;
       };
+
+      #                              ↓Things available only to packages in the scope↓
+      callPackage = self.newScope { inherit qtbase-bootstrap qttools-bootstrap stdenv; };
     in
     {
 
@@ -282,14 +293,7 @@ let
       qtbase = callPackage ../modules/qtbase.nix {
         inherit (srcs.qtbase) src version;
         patches = patches.qtbase;
-        inherit
-          bison
-          cups
-          harfbuzz
-          libGL
-          ;
         withGtk3 = !stdenv.hostPlatform.isDarwin;
-        inherit dconf gtk3;
         inherit developerBuild decryptSslTraffic;
       };
 
@@ -305,9 +309,7 @@ let
       qtlocation = callPackage ../modules/qtlocation.nix { };
       qtlottie = callPackage ../modules/qtlottie.nix { };
       qtmacextras = callPackage ../modules/qtmacextras.nix { };
-      qtmultimedia = callPackage ../modules/qtmultimedia.nix {
-        inherit gstreamer gst-plugins-base;
-      };
+      qtmultimedia = callPackage ../modules/qtmultimedia.nix { };
       qtnetworkauth = callPackage ../modules/qtnetworkauth.nix { };
       qtpim = callPackage ../modules/qtpim.nix { };
       qtpositioning = callPackage ../modules/qtpositioning.nix { };
@@ -330,22 +332,13 @@ let
       qtvirtualkeyboard = callPackage ../modules/qtvirtualkeyboard.nix { };
       qtwayland = callPackage ../modules/qtwayland.nix { };
       qtwebchannel = callPackage ../modules/qtwebchannel.nix { };
-      qtwebengine =
-        # Actually propagating stdenv change
-        let
-          # Won’t build with Clang 20, as `-Wenum-constexpr-conversion`
-          # was made a hard error.
-          # qt5webengine no longer maintained, FTBFS with GCC 15
-          stdenv' = if stdenv.cc.isClang then llvmPackages_19.stdenv else gcc14Stdenv;
-          qtModule' = qtModuleWithStdenv stdenv';
-        in
-        callPackage ../modules/qtwebengine.nix {
-          inherit (srcs.qtwebengine) version;
-          inherit (darwin) bootstrap_cmds;
-          stdenv = stdenv';
-          qtModule = qtModule';
-          python = python3;
-        };
+      qtwebengine = callPackage ../modules/qtwebengine.nix {
+        # Won’t build with Clang 20, as `-Wenum-constexpr-conversion`
+        # was made a hard error.
+        stdenv = if stdenv.cc.isClang then llvmPackages_19.stdenv else stdenv;
+        inherit (srcs.qtwebengine) version;
+        inherit (darwin) bootstrap_cmds;
+      };
       qtwebglplugin = callPackage ../modules/qtwebglplugin.nix { };
       qtwebkit = callPackage ../modules/qtwebkit.nix { };
       qtwebsockets = callPackage ../modules/qtwebsockets.nix { };
@@ -356,16 +349,10 @@ let
       env = callPackage ../qt-env.nix { };
 
       qmake = callPackage (
-        { qtbase }:
+        { qtbase-bootstrap }:
         makeSetupHook {
           name = "qmake-hook";
-          ${
-            if stdenv.buildPlatform == stdenv.hostPlatform then
-              "propagatedBuildInputs"
-            else
-              "depsTargetTargetPropagated"
-          } =
-            [ qtbase.dev ];
+          propagatedBuildInputs = [ qtbase-bootstrap.qmake ];
           substitutions = {
             inherit debug;
             fix_qmake_libtool = ../hooks/fix-qmake-libtool.sh;
@@ -381,9 +368,9 @@ let
         }:
         makeSetupHook {
           name = "wrap-qt5-apps-hook";
-          propagatedBuildInputs = [
+          propagatedBuildInputs = [ makeBinaryWrapper ];
+          depsTargetTargetPropagated = [
             qtbase.dev
-            makeBinaryWrapper
           ]
           ++ lib.optional stdenv.hostPlatform.isLinux qtwayland.dev;
         } ../hooks/wrap-qt-apps-hook.sh
@@ -393,25 +380,10 @@ let
       full = throw "libsForQt5.full has been removed. Please use individual packages instead."; # Added 2025-10-18
     };
 
-  baseScope = makeScopeWithSplicing' {
+  finalScope = makeScopeWithSplicing' {
     otherSplices = generateSplicesForMkScope "qt5";
     f = addPackages;
   };
 
-  bootstrapScope = baseScope.overrideScope (
-    final: prev: {
-      qtbase = prev.qtbase.override { qttranslations = null; };
-      qtdeclarative = null;
-    }
-  );
-
-  finalScope = baseScope.overrideScope (
-    final: prev: {
-      # qttranslations causes eval-time infinite recursion when
-      # cross-compiling; disabled for now.
-      qttranslations =
-        if stdenv.buildPlatform == stdenv.hostPlatform then bootstrapScope.qttranslations else null;
-    }
-  );
 in
 finalScope
diff --git a/pkgs/development/libraries/qt-5/5.15/qtbase.patch.d/0015-qtbase-cross-build.patch b/pkgs/development/libraries/qt-5/5.15/qtbase.patch.d/0015-qtbase-cross-build.patch
new file mode 100644
index 0000000000000..644ddc6d9ea1c
--- /dev/null
+++ b/pkgs/development/libraries/qt-5/5.15/qtbase.patch.d/0015-qtbase-cross-build.patch
@@ -0,0 +1,197 @@
+diff --git a/mkspecs/features/device_config.prf b/mkspecs/features/device_config.prf
+index c15559e174..023a4bcb35 100644
+--- a/mkspecs/features/device_config.prf
++++ b/mkspecs/features/device_config.prf
+@@ -1,9 +1,5 @@
+ # This file is loaded by some qmakespecs to get early configuration data.
+ 
+-# Some of these qmakespecs can be used also in host mode, but they are not
+-# supposed to be influenced by -device-option then.
+-host_build: return()
+-
+ DEVICE_PRI = $$[QT_HOST_DATA/get]/mkspecs/qdevice.pri
+ exists($$DEVICE_PRI):include($$DEVICE_PRI)
+ unset(DEVICE_PRI)
+diff --git a/mkspecs/features/qt_build_config.prf b/mkspecs/features/qt_build_config.prf
+index 511b158b91..70d1e10611 100644
+--- a/mkspecs/features/qt_build_config.prf
++++ b/mkspecs/features/qt_build_config.prf
+@@ -15,6 +15,13 @@
+         debug(1, "Cannot load qmodule.pri!")
+     } else {
+         debug(1, "Loaded qmodule.pri from ($$QMAKE_QT_MODULE)")
++
++        # Yeah, there are multiple pkg-config related varialbes and functions
++        # that are used throughout QT modules somewhat interchangeably.
++        # As we're now trying to build all packaged binaries for the hostPlatform
++        # only, let's not create even more confusion and just follow a simple rule:
++        # always get pkg-config from the PKG_CONFIG env variable.
++        PKG_CONFIG_EXECUTABLE = $$(PKG_CONFIG)
+     }
+ } else {
+     debug(1, "Not loading qmodule.pri twice")
+diff --git a/mkspecs/features/qt_configure.prf b/mkspecs/features/qt_configure.prf
+index 6537d98c5d..19ed05db61 100644
+--- a/mkspecs/features/qt_configure.prf
++++ b/mkspecs/features/qt_configure.prf
+@@ -423,16 +423,7 @@ defineReplace(qtConfPkgConfigEnv) {
+ }
+ 
+ defineReplace(qtConfPkgConfig) {
+-    host = $$1
+-    isEmpty(host): host = false
+-
+-    $$host {
+-        pkg_config = $$qtConfFindInPath("pkg-config")
+-    } else {
+-        pkg_config = "$$qtConfPkgConfigEnv()$$PKG_CONFIG_EXECUTABLE"
+-    }
+-
+-    return($$pkg_config)
++    return($$getenv("PKG_CONFIG"))
+ }
+ 
+ defineTest(qtConfPkgConfigPackageExists) {
+diff --git a/mkspecs/features/qt_tool.prf b/mkspecs/features/qt_tool.prf
+index a8d589f0fa..3d0f832a6b 100644
+--- a/mkspecs/features/qt_tool.prf
++++ b/mkspecs/features/qt_tool.prf
+@@ -18,7 +18,7 @@ DEFINES *= QT_USE_QSTRINGBUILDER
+ # If we are doing a prefix build, create a "module" pri which enables
+ # qtPrepareTool() to work with the non-installed build.
+ # Non-bootstrapped tools always need this because of the environment setup.
+-!build_pass:if(!host_build|!force_bootstrap|force_independent|!isEmpty(HOST_QT_TOOLS)) {
++!build_pass:if(!host_build|!force_bootstrap|force_independent|cross_compile) {
+     isEmpty(MODULE):MODULE = $$TARGET
+ 
+     load(qt_build_paths)
+@@ -27,7 +27,7 @@ DEFINES *= QT_USE_QSTRINGBUILDER
+ 
+     vars = binary depends
+ 
+-    !host_build|isEmpty(HOST_QT_TOOLS) {
++    !host_build|!cross_compile {
+         load(resolve_target)
+ 
+         !host_build|!force_bootstrap: MODULE_DEPENDS = $$replace(QT, -private$, _private)
+@@ -55,6 +55,10 @@ DEFINES *= QT_USE_QSTRINGBUILDER
+         bin = $${HOST_QT_TOOLS}/$${TARGET}
+         equals(QMAKE_HOST.os, Windows): bin = $${bin}.exe
+         bin = $$system_path($$bin)
++        !exists($$bin) {
++            # search in PATH as a fallback
++            bin = $$system("command -v $${TARGET}")
++        }
+     }
+ 
+     TOOL_PRI_CONT = \
+diff --git a/src/corelib/Qt5CoreConfigExtras.cmake.in b/src/corelib/Qt5CoreConfigExtras.cmake.in
+index be07a2e1e8..0b9c425ec8 100644
+--- a/src/corelib/Qt5CoreConfigExtras.cmake.in
++++ b/src/corelib/Qt5CoreConfigExtras.cmake.in
+@@ -5,30 +5,20 @@ endif()
+ if (NOT TARGET Qt5::qmake)
+     add_executable(Qt5::qmake IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"$$NIX_OUTPUT_DEV/$${CMAKE_BIN_DIR}qmake$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}qmake$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_Core_check_file_exists(${imported_location})
++    find_program(qmake_imported_location \"qmake$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qmake PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qmake_imported_location}
+     )
+ endif()
+ 
+ if (NOT TARGET Qt5::moc)
+     add_executable(Qt5::moc IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"$$NIX_OUTPUT_DEV/$${CMAKE_BIN_DIR}moc$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}moc$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_Core_check_file_exists(${imported_location})
++    find_program(moc_imported_location \"moc$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::moc PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${moc_imported_location}
+     )
+     # For CMake automoc feature
+     get_target_property(QT_MOC_EXECUTABLE Qt5::moc LOCATION)
+@@ -37,15 +27,10 @@ endif()
+ if (NOT TARGET Qt5::rcc)
+     add_executable(Qt5::rcc IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"$$NIX_OUTPUT_DEV/$${CMAKE_BIN_DIR}rcc$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}rcc$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_Core_check_file_exists(${imported_location})
++    find_program(rcc_imported_location \"rcc$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::rcc PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${rcc_imported_location}
+     )
+ endif()
+ 
+diff --git a/src/dbus/Qt5DBusConfigExtras.cmake.in b/src/dbus/Qt5DBusConfigExtras.cmake.in
+index b13b964ec8..f4b7109037 100644
+--- a/src/dbus/Qt5DBusConfigExtras.cmake.in
++++ b/src/dbus/Qt5DBusConfigExtras.cmake.in
+@@ -2,22 +2,20 @@
+ if (NOT TARGET Qt5::qdbuscpp2xml)
+     add_executable(Qt5::qdbuscpp2xml IMPORTED)
+ 
+-    set(imported_location \"$$NIX_OUTPUT_DEV/bin/qdbuscpp2xml$$CMAKE_BIN_SUFFIX\")
+-    _qt5_DBus_check_file_exists(${imported_location})
++    find_program(qdbuscpp2xml_imported_location \"qdbuscpp2xml$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qdbuscpp2xml PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qdbuscpp2xml_imported_location}
+     )
+ endif()
+ 
+ if (NOT TARGET Qt5::qdbusxml2cpp)
+     add_executable(Qt5::qdbusxml2cpp IMPORTED)
+ 
+-    set(imported_location \"$$NIX_OUTPUT_DEV/bin/qdbusxml2cpp$$CMAKE_BIN_SUFFIX\")
+-    _qt5_DBus_check_file_exists(${imported_location})
++    find_program(qdbusxml2cpp_imported_location \"qdbusxml2cpp$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qdbusxml2cpp PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qdbusxml2cpp_imported_location}
+     )
+ endif()
+ 
+diff --git a/src/widgets/Qt5WidgetsConfigExtras.cmake.in b/src/widgets/Qt5WidgetsConfigExtras.cmake.in
+index ca0b8e4bfb..f49f09fed2 100644
+--- a/src/widgets/Qt5WidgetsConfigExtras.cmake.in
++++ b/src/widgets/Qt5WidgetsConfigExtras.cmake.in
+@@ -2,15 +2,10 @@
+ if (NOT TARGET Qt5::uic)
+     add_executable(Qt5::uic IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"$$NIX_OUTPUT_DEV/$${CMAKE_BIN_DIR}uic$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}uic$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_Widgets_check_file_exists(${imported_location})
++    find_program(uic_imported_location \"uic$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::uic PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${uic_imported_location}
+     )
+ endif()
+ 
diff --git a/pkgs/development/libraries/qt-5/5.15/qtbase.patch.d/0016-qtbase-cross-build-postFixup.patch b/pkgs/development/libraries/qt-5/5.15/qtbase.patch.d/0016-qtbase-cross-build-postFixup.patch
new file mode 100644
index 0000000000000..465abaeaff3b7
--- /dev/null
+++ b/pkgs/development/libraries/qt-5/5.15/qtbase.patch.d/0016-qtbase-cross-build-postFixup.patch
@@ -0,0 +1,40 @@
+diff --git a/mkspecs/features/qt_build_config.prf b/mkspecs/features/qt_build_config.prf
+index 70d1e10611..ce8b9383eb 100644
+--- a/mkspecs/features/qt_build_config.prf
++++ b/mkspecs/features/qt_build_config.prf
+@@ -16,6 +16,12 @@
+     } else {
+         debug(1, "Loaded qmodule.pri from ($$QMAKE_QT_MODULE)")
+ 
++        # detect cross compilation status dynamically for the case of
++        # switching cross and natively built qtbase
++        _crossComp = $$(XQMAKESPEC)
++        isEmpty(_crossComp): CONFIG -= cross_compile
++        else: CONFIG += cross_compile
++
+         # Yeah, there are multiple pkg-config related varialbes and functions
+         # that are used throughout QT modules somewhat interchangeably.
+         # As we're now trying to build all packaged binaries for the hostPlatform
+diff --git a/mkspecs/features/qt_config.prf b/mkspecs/features/qt_config.prf
+index 93c54e3010..65552276ac 100644
+--- a/mkspecs/features/qt_config.prf
++++ b/mkspecs/features/qt_config.prf
+@@ -5,6 +5,18 @@ QMAKE_QT_CONFIG = $$[QT_HOST_DATA/get]/mkspecs/qconfig.pri
+    debug(1, "Cannot load qconfig.pri!")
+ } else {
+    debug(1, "Loaded .qconfig.pri from ($$QMAKE_QT_CONFIG)")
++
++   # detect cross compilation status dynamically for the case of
++   # switching cross and natively built qtbase
++   _crossComp = $$(XQMAKESPEC)
++   isEmpty(_crossComp) {
++      QT.global.enabled_features -= cross_compile
++      CONFIG -= cross_compile
++   } else {
++      QT.global.enabled_features += cross_compile
++      CONFIG += cross_compile
++   }
++
+    dirs = $$(QMAKEMODULES)
+    QMAKE_MODULE_PATH = $$split(dirs, $$DIRLIST_SEPARATOR)
+    QMAKE_MODULE_PATH += $$QMAKEMODULES
diff --git a/pkgs/development/libraries/qt-5/5.15/qtdeclarative-cross-build.patch b/pkgs/development/libraries/qt-5/5.15/qtdeclarative-cross-build.patch
new file mode 100644
index 0000000000000..ca41a9320f02a
--- /dev/null
+++ b/pkgs/development/libraries/qt-5/5.15/qtdeclarative-cross-build.patch
@@ -0,0 +1,38 @@
+diff --git a/tools/qmlcachegen/Qt5QuickCompilerConfig.cmake.in b/tools/qmlcachegen/Qt5QuickCompilerConfig.cmake.in
+index 8a91fb8b87..b0f7cac849 100644
+--- a/tools/qmlcachegen/Qt5QuickCompilerConfig.cmake.in
++++ b/tools/qmlcachegen/Qt5QuickCompilerConfig.cmake.in
+@@ -18,11 +18,8 @@ function(QTQUICK_COMPILER_ADD_RESOURCES outfiles)
+ 
+     find_package(Qt5 COMPONENTS Qml Core)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(compiler_path \"${_qt5Core_install_prefix}/$${CMAKE_BIN_DIR}qmlcachegen$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(compiler_path \"$${CMAKE_BIN_DIR}qmlcachegen$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
++    find_program(compiler_path \"qmlcachegen$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
++
+     if(NOT EXISTS \"${compiler_path}\" )
+         message(FATAL_ERROR \"The package \\\"Qt5QuickCompilerConfig\\\" references the file
+    \\\"${compiler_path}\\\"
+diff --git a/tools/qmlimportscanner/Qt5QmlImportScannerConfig.cmake.in b/tools/qmlimportscanner/Qt5QmlImportScannerConfig.cmake.in
+index f92b8d295d..c85ec4d206 100644
+--- a/tools/qmlimportscanner/Qt5QmlImportScannerConfig.cmake.in
++++ b/tools/qmlimportscanner/Qt5QmlImportScannerConfig.cmake.in
+@@ -13,12 +13,9 @@ function(QT5_IMPORT_QML_PLUGINS target)
+ 
+     # Find location of qmlimportscanner.
+     find_package(Qt5 COMPONENTS Core)
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(tool_path
+-        \"${_qt5Core_install_prefix}/$${CMAKE_BIN_DIR}qmlimportscanner$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(tool_path \"$${CMAKE_BIN_DIR}qmlimportscanner$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
++
++    find_program(tool_path \"qmlimportscanner$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
++
+     if(NOT EXISTS \"${tool_path}\" )
+         message(FATAL_ERROR \"The package \\\"Qt5QmlImportScannerConfig\\\" references the file
+    \\\"${tool_path}\\\"
diff --git a/pkgs/development/libraries/qt-5/5.15/qtdeclarative-gcc15.patch b/pkgs/development/libraries/qt-5/5.15/qtdeclarative-gcc15.patch
new file mode 100644
index 0000000000000..87b70dc8d749f
--- /dev/null
+++ b/pkgs/development/libraries/qt-5/5.15/qtdeclarative-gcc15.patch
@@ -0,0 +1,12 @@
+diff --git a/src/qml/compiler/qv4compiler.cpp b/src/qml/compiler/qv4compiler.cpp
+index 18e19cf01c..13934eebb5 100644
+--- a/src/qml/compiler/qv4compiler.cpp
++++ b/src/qml/compiler/qv4compiler.cpp
+@@ -47,6 +47,7 @@
+ #include <private/qml_compile_hash_p.h>
+ #include <private/qqmlirbuilder_p.h>
+ #include <QCryptographicHash>
++#include <cstdint>
+ 
+ // Efficient implementation that takes advantage of powers of two.
+ static inline size_t roundUpToMultipleOf(size_t divisor, size_t x)
diff --git a/pkgs/development/libraries/qt-5/5.15/qttools-cross-build.patch b/pkgs/development/libraries/qt-5/5.15/qttools-cross-build.patch
new file mode 100644
index 0000000000000..e97105d0c2cf8
--- /dev/null
+++ b/pkgs/development/libraries/qt-5/5.15/qttools-cross-build.patch
@@ -0,0 +1,139 @@
+diff --git a/src/assistant/help/Qt5HelpConfigExtras.cmake.in b/src/assistant/help/Qt5HelpConfigExtras.cmake.in
+index 1f7544b62..bd18710f9 100644
+--- a/src/assistant/help/Qt5HelpConfigExtras.cmake.in
++++ b/src/assistant/help/Qt5HelpConfigExtras.cmake.in
+@@ -2,30 +2,20 @@
+ if (NOT TARGET Qt5::qcollectiongenerator)
+     add_executable(Qt5::qcollectiongenerator IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5Help_install_prefix}/$${CMAKE_BIN_DIR}qcollectiongenerator$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}qcollectiongenerator$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_Help_check_file_exists(${imported_location})
++    find_program(qcollectiongenerator_imported_location \"qcollectiongenerator$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qcollectiongenerator PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qcollectiongenerator_imported_location}
+     )
+ endif()
+ 
+ if (NOT TARGET Qt5::qhelpgenerator)
+     add_executable(Qt5::qhelpgenerator IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5Help_install_prefix}/$${CMAKE_BIN_DIR}qhelpgenerator$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}qhelpgenerator$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_Help_check_file_exists(${imported_location})
++    find_program(qhelpgenerator_imported_location \"qhelpgenerator$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qhelpgenerator PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qhelpgenerator_imported_location}
+     )
+ endif()
+ 
+diff --git a/src/linguist/Qt5LinguistToolsConfig.cmake.in b/src/linguist/Qt5LinguistToolsConfig.cmake.in
+index 2e99bc762..36af1a596 100644
+--- a/src/linguist/Qt5LinguistToolsConfig.cmake.in
++++ b/src/linguist/Qt5LinguistToolsConfig.cmake.in
+@@ -44,45 +44,30 @@ endmacro()
+ if (NOT TARGET Qt5::lrelease)
+     add_executable(Qt5::lrelease IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5_linguisttools_install_prefix}/$${CMAKE_BIN_DIR}lrelease$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}lrelease$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_LinguistTools_check_file_exists(${imported_location})
++    find_program(lrelease_imported_location \"lrelease$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::lrelease PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${lrelease_imported_location}
+     )
+ endif()
+ 
+ if (NOT TARGET Qt5::lupdate)
+     add_executable(Qt5::lupdate IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5_linguisttools_install_prefix}/$${CMAKE_BIN_DIR}lupdate$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}lupdate$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_LinguistTools_check_file_exists(${imported_location})
++    find_program(lupdate_imported_location \"lupdate$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::lupdate PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${lupdate_imported_location}
+     )
+ endif()
+ 
+ if (NOT TARGET Qt5::lconvert)
+     add_executable(Qt5::lconvert IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5_linguisttools_install_prefix}/$${CMAKE_BIN_DIR}lconvert$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}lconvert$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_LinguistTools_check_file_exists(${imported_location})
++    find_program(lconvert_imported_location \"lconvert$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::lconvert PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${lconvert_imported_location}
+     )
+ endif()
+ 
+diff --git a/src/qdoc/Qt5DocToolsConfig.cmake.in b/src/qdoc/Qt5DocToolsConfig.cmake.in
+index 2a252bb31..6b2555c4d 100644
+--- a/src/qdoc/Qt5DocToolsConfig.cmake.in
++++ b/src/qdoc/Qt5DocToolsConfig.cmake.in
+@@ -43,15 +43,10 @@ endmacro()
+ if (NOT TARGET Qt5::qdoc)
+     add_executable(Qt5::qdoc IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5_qdoctools_install_prefix}/$${CMAKE_BIN_DIR}qdoc$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}qdoc$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_DocTools_check_file_exists(${imported_location})
++    find_program(qdoc_imported_location \"qdoc$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qdoc PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qdoc_imported_location}
+     )
+ endif()
+ 
+diff --git a/src/qtattributionsscanner/Qt5AttributionsScannerTools.cmake.in b/src/qtattributionsscanner/Qt5AttributionsScannerTools.cmake.in
+index e99540bfa..85171c76b 100644
+--- a/src/qtattributionsscanner/Qt5AttributionsScannerTools.cmake.in
++++ b/src/qtattributionsscanner/Qt5AttributionsScannerTools.cmake.in
+@@ -43,15 +43,10 @@ endmacro()
+ if (NOT TARGET Qt5::qtattributionsscanner)
+     add_executable(Qt5::qtattributionsscanner IMPORTED)
+ 
+-!!IF isEmpty(CMAKE_BIN_DIR_IS_ABSOLUTE)
+-    set(imported_location \"${_qt5_qattributionsscannertools_install_prefix}/$${CMAKE_BIN_DIR}qtattributionsscanner$$CMAKE_BIN_SUFFIX\")
+-!!ELSE
+-    set(imported_location \"$${CMAKE_BIN_DIR}qtattributionsscanner$$CMAKE_BIN_SUFFIX\")
+-!!ENDIF
+-    _qt5_AttributionsScannerTools_check_file_exists(${imported_location})
++    find_program(qtattributionsscanner_imported_location \"qtattributionsscanner$$CMAKE_BIN_SUFFIX\" PATHS ENV PATH NO_DEFAULT_PATH)
+ 
+     set_target_properties(Qt5::qtattributionsscanner PROPERTIES
+-        IMPORTED_LOCATION ${imported_location}
++        IMPORTED_LOCATION ${qtattributionsscanner_imported_location}
+     )
+ endif()
+ 
diff --git a/pkgs/development/libraries/qt-5/5.15/qtwebengine-cross-build.patch b/pkgs/development/libraries/qt-5/5.15/qtwebengine-cross-build.patch
new file mode 100644
index 0000000000000..81e18bbc65107
--- /dev/null
+++ b/pkgs/development/libraries/qt-5/5.15/qtwebengine-cross-build.patch
@@ -0,0 +1,149 @@
+commit 8d8892f237a510a614311e37ebcc4d70b71b7924
+Author:     eryngion <eryngion@protonmail.com>
+AuthorDate: Fri Dec 1 10:59:02 2023 +0300
+
+    Use buildBuld version of stdenv.cc in the "host" toolchain for chromium
+    
+    Chromium builds some tools for itself as a part of its build process.
+    Those tools don't end up in outputs of Nix packages, so we can actually
+    just compile them for the buildPlatform.
+    
+    It is mostly a Nixified version of this patch
+    https://github.com/meta-qt5/meta-qt5/raw/9537acc9fdd07f2dae6ea562eed34ba41ccde39d/recipes-qt/qt5/qtwebengine/0001-Force-host-toolchain-configuration.patch
+    Plus a small change that allows v8_snapshot_toolchain to properly find ICU
+    on the buildPlatform instead of resorting to the bundled ICU as done in
+    https://github.com/meta-qt5/meta-qt5/blob/9537acc9fdd07f2dae6ea562eed34ba41ccde39d/recipes-qt/qt5/qtwebengine/chromium/0010-chromium-icu-use-system-library-only-targets.patch
+    
+    The original commentary of the first patch is below:
+    
+    From: Samuli Piippo <samuli.piippo@qt.io>
+    Date: Wed, 15 Mar 2017 13:53:28 +0200
+    Subject: [PATCH] Force host toolchain configuration
+    
+    Force gcc/g++ to be used for parts using host toolchain, since
+    the option(host_build) does not work in yocto builds.
+    
+    Don't use QT_ARCH for the host architecture, since that's always
+    the target architecture in bitbake builds, instead ask specifically
+    for the qmakes's host architecture.
+    
+    Upstream-Status: Inappropriate [OE specific]
+    Signed-off-by: Samuli Piippo <samuli.piippo@qt.io>
+
+diff --git a/mkspecs/features/functions.prf b/mkspecs/features/functions.prf
+index 7f63058..6b658e8 100644
+--- a/mkspecs/features/functions.prf
++++ b/mkspecs/features/functions.prf
+@@ -109,6 +109,7 @@ defineReplace(gnArch) {
+     contains(qtArch, "x86_64"): return(x64)
+     contains(qtArch, "arm"): return(arm)
+     contains(qtArch, "arm64"): return(arm64)
++    contains(qtArch, "aarch64"): return(arm64)
+     contains(qtArch, "mips"): return(mipsel)
+     contains(qtArch, "mips64"): return(mips64el)
+     contains(qtArch, "mips64el"): return(mips64el)
+diff --git a/src/buildtools/config/linux.pri b/src/buildtools/config/linux.pri
+index 7507d51..5bc9c1b 100644
+--- a/src/buildtools/config/linux.pri
++++ b/src/buildtools/config/linux.pri
+@@ -118,7 +118,7 @@ contains(QT_ARCH, "mips") {
+ 
+ host_build {
+     gn_args += custom_toolchain=\"$$QTWEBENGINE_OUT_ROOT/src/toolchain:host\"
+-    GN_HOST_CPU = $$gnArch($$QT_ARCH)
++    GN_HOST_CPU = $$gnArch($$QMAKE_HOST.arch)
+     gn_args += host_cpu=\"$$GN_HOST_CPU\"
+     # Don't bother trying to use system libraries in this case
+     gn_args += use_glib=false
+@@ -138,7 +138,7 @@ host_build {
+         # Strip '>2 /dev/null' from $$pkgConfigExecutable()
+         PKGCONFIG = $$first($$list($$pkgConfigExecutable()))
+         gn_args += pkg_config=\"$$PKGCONFIG\"
+-        PKG_CONFIG_HOST = $$(GN_PKG_CONFIG_HOST)
++        PKG_CONFIG_HOST = $$(PKG_CONFIG_FOR_BUILD)
+         pkgConfigLibDir = $$(PKG_CONFIG_LIBDIR)
+         pkgConfigSysrootDir = $$(PKG_CONFIG_SYSROOT_DIR)
+         isEmpty(PKG_CONFIG_HOST): cross_compile {
+diff --git a/src/buildtools/configure_host.pro b/src/buildtools/configure_host.pro
+index dd0d3e3..8703801 100644
+--- a/src/buildtools/configure_host.pro
++++ b/src/buildtools/configure_host.pro
+@@ -4,7 +4,7 @@ TEMPLATE = aux
+ # Pick up the host toolchain
+ option(host_build)
+ 
+-GN_HOST_CPU = $$gnArch($$QT_ARCH)
++GN_HOST_CPU = $$gnArch($$QMAKE_HOST.arch)
+ !isEmpty(QT_TARGET_ARCH): GN_TARGET_CPU = $$gnArch($$QT_TARGET_ARCH)
+ else: GN_TARGET_CPU = $$GN_HOST_CPU
+ GN_OS = $$gnOS()
+@@ -23,20 +23,17 @@ contains(GN_TARGET_CPU, "arm")|contains(GN_TARGET_CPU, "mipsel")|contains(GN_TAR
+     else: contains(GN_V8_HOST_CPU, mips64el): GN_V8_HOST_CPU = "mipsel"
+ }
+ 
+-GN_HOST_EXTRA_CPPFLAGS = $$(GN_HOST_TOOLCHAIN_EXTRA_CPPFLAGS)
+-
+ # We always use the gcc_toolchain, because clang_toolchain is just
+ # a broken wrapper around it for Google's custom clang binaries.
+ GN_CONTENTS = \
+ "import(\"//build/config/sysroot.gni\")" \
+ "import(\"//build/toolchain/gcc_toolchain.gni\")" \
+ "gcc_toolchain(\"host\") {" \
+-"  cc = \"$$which($$QMAKE_CC)\" " \
+-"  cxx = \"$$which($$QMAKE_CXX)\" " \
+-"  ld = \"$$which($$QMAKE_LINK)\" " \
+-"  ar = \"$$which(ar)\" " \
+-"  nm = \"$$which(nm)\" " \
+-"  extra_cppflags = \"$$GN_HOST_EXTRA_CPPFLAGS\" " \
++"  cc = \"$$which($$(CC_FOR_BUILD))\" " \
++"  cxx = \"$$which($$(CXX_FOR_BUILD))\" " \
++"  ld = \"$$which($$(CXX_FOR_BUILD))\" " \
++"  ar = \"$$which($$(AR_FOR_BUILD))\" " \
++"  nm = \"$$which($$(NM_FOR_BUILD))\" " \
+ "  toolchain_args = { " \
+ "    current_os = \"$$GN_OS\" " \
+ "    current_cpu = \"$$GN_HOST_CPU\" " \
+@@ -45,11 +42,11 @@ GN_CONTENTS = \
+ "  } " \
+ "}" \
+ "gcc_toolchain(\"v8_snapshot\") {" \
+-"  cc = \"$$which($$QMAKE_CC)\" " \
+-"  cxx = \"$$which($$QMAKE_CXX)\" " \
+-"  ld = \"$$which($$QMAKE_LINK)\" " \
+-"  ar = \"$$which(ar)\" " \
+-"  nm = \"$$which(nm)\" " \
++"  cc = \"$$which($$(CC_FOR_BUILD))\" " \
++"  cxx = \"$$which($$(CXX_FOR_BUILD))\" " \
++"  ld = \"$$which($$(CXX_FOR_BUILD))\" " \
++"  ar = \"$$which($$(AR_FOR_BUILD))\" " \
++"  nm = \"$$which($$(NM_FOR_BUILD))\" " \
+ "  toolchain_args = { " \
+ "    current_os = \"$$GN_OS\" " \
+ "    current_cpu = \"$$GN_V8_HOST_CPU\" " \
+diff --git a/src/buildtools/gn.pro b/src/buildtools/gn.pro
+index f94694d..8035d5a 100644
+--- a/src/buildtools/gn.pro
++++ b/src/buildtools/gn.pro
+@@ -19,9 +19,8 @@ build_pass|!debug_and_release {
+             gn_bootstrap = $$system_path($$absolute_path(gn/build/gen.py, $$src_3rd_party_dir))
+ 
+             gn_gen_args = --no-last-commit-position --out-path $$out_path \
+-                          --cc \"$$which($$QMAKE_CC)\" --cxx \"$$which($$QMAKE_CXX)\" \
+-                          --ld \"$$which($$QMAKE_LINK)\"
+-            !isEmpty(QMAKE_AR): gn_gen_args += --ar \"$$which($$first(QMAKE_AR))\"
++                          --cc \"$$which($$(CC_FOR_BUILD))\" --cxx \"$$which($$(CXX_FOR_BUILD))\" \
++                          --ld \"$$which($$(CXX_FOR_BUILD))\" --ar \"$$which($$(AR_FOR_BUILD))\"
+ 
+             msvc:!clang_cl: gn_gen_args += --use-lto
+ 
+--- a/src/3rdparty/chromium/build/config/linux/pkg_config.gni
++++ b/src/3rdparty/chromium/build/config/linux/pkg_config.gni
+@@ -91,7 +91,7 @@
+   assert(defined(invoker.packages),
+          "Variable |packages| must be defined to be a list in pkg_config.")
+   config(target_name) {
+-    if (host_toolchain == current_toolchain) {
++    if (default_toolchain != current_toolchain) {
+       args = host_pkg_config_args + invoker.packages
+     } else {
+       args = pkg_config_args + invoker.packages
diff --git a/pkgs/development/libraries/qt-5/hooks/fix-qt-module-paths.sh b/pkgs/development/libraries/qt-5/hooks/fix-qt-module-paths.sh
index 33682f6f3c695..f7e3f97865a35 100644
--- a/pkgs/development/libraries/qt-5/hooks/fix-qt-module-paths.sh
+++ b/pkgs/development/libraries/qt-5/hooks/fix-qt-module-paths.sh
@@ -4,6 +4,15 @@
 #
 # Find Qt module definitions in directory _dir_ and patch the module paths.
 #
+
+lndir() {
+    local link_to_dir=$(realpath "$1")
+    local link_from_dir=$(realpath "$2")
+    for f in $(ls "$link_to_dir"); do
+        ln -s "$link_to_dir/$f" "$link_from_dir/$f"
+    done
+}
+
 fixQtModulePaths () {
     local dir="$1"
     local bin="${!outputBin}"
@@ -30,7 +39,7 @@ fixQtModulePaths () {
     if [ "z$bin" != "z$dev" ]; then
         if [ -d "$bin/bin" ]; then
             mkdir -p "$dev/bin"
-            lndir -silent "$bin/bin" "$dev/bin"
+            lndir "$bin/bin" "$dev/bin"
         fi
     fi
 }
diff --git a/pkgs/development/libraries/qt-5/hooks/qmake-hook.sh b/pkgs/development/libraries/qt-5/hooks/qmake-hook.sh
index 855efb5e6c0fd..c0f2b3916b224 100644
--- a/pkgs/development/libraries/qt-5/hooks/qmake-hook.sh
+++ b/pkgs/development/libraries/qt-5/hooks/qmake-hook.sh
@@ -1,5 +1,15 @@
 . @fix_qmake_libtool@
 
+# Split qmakeFlags if it's not an array already (i.e. comes from a derivation
+# with __structuredAttrs disabled). This will be important later when we pass
+# it to qmake: qmakeFlags can contain file names and other options that must
+# be separate words in the command.
+local type=$(declare -p qmakeFlags)
+local typeArray='declare -a'
+if [[ "${type:0:${#typeArray}}" == "$typeArray" ]]; then
+    qmakeFlags=( ${qmakeFlags-} )
+fi
+
 qmakePrePhase() {
     # These flags must be added _before_ the flags specified in the derivation.
     prependToVar qmakeFlags \
diff --git a/pkgs/development/libraries/qt-5/hooks/qtbase-setup-hook.sh b/pkgs/development/libraries/qt-5/hooks/qtbase-setup-hook.sh
index 1a9b940328682..2ec6fb001e4de 100644
--- a/pkgs/development/libraries/qt-5/hooks/qtbase-setup-hook.sh
+++ b/pkgs/development/libraries/qt-5/hooks/qtbase-setup-hook.sh
@@ -30,20 +30,41 @@ else
     cmakeBuildType="Release"
 fi
 
+isCrossBuild() {
+    # Check if the tool is prefixed. Will probably break on Windows.
+    # Maybe we should have a standard variable for this?
+    [[ -v AS ]] && [[ "${#AS}" -gt 2 ]]
+}
+
+if isCrossBuild; then
+    # When cross compiling we're using a native-built qmake binary and
+    # it will need a little help finding the target of cross compilation.
+    if nixCrossConf="$(basename $(ls -d @dev@/mkspecs/*-nix-cross))"; then
+        # Force qmake to use this config as the target instead of QMAKE_XSPEC
+        # that was baked into it at compile time.
+        export "XQMAKESPEC=$nixCrossConf"
+        # Use the same config for tools marked with host_build
+        export "QMAKESPEC=$XQMAKESPEC"
+    else
+        echo "Please add a qtPlatformCross entry for $($CC -dumpmachine)" >&2
+        exit 1
+    fi
+fi
+
 providesQtRuntime() {
     [ -d "$1/$qtPluginPrefix" ] || [ -d "$1/$qtQmlPrefix" ]
 }
 
+if ! QMAKE="$(PATH="$_PATH" command -v qmake)"; then
+    echo "FYI: can't find a runnable qmake in PATH. If nothing breaks than it's perfectly fine."
+    echo "Otherwise you should add qmake or qtbase.qmake to nativeBuildInputs."
+fi
 # Build tools are often confused if QMAKE is unset.
-QMAKE=@dev@/bin/qmake
 export QMAKE
 
 QMAKEPATH=
 export QMAKEPATH
 
-QMAKEMODULES=
-export QMAKEMODULES
-
 declare -Ag qmakePathSeen=()
 qmakePathHook() {
     # Skip this path if we have seen it before.
@@ -52,11 +73,10 @@ qmakePathHook() {
     qmakePathSeen[$1]=1
     if [ -d "$1/mkspecs" ]
     then
-        QMAKEMODULES="${QMAKEMODULES}${QMAKEMODULES:+:}/mkspecs"
         QMAKEPATH="${QMAKEPATH}${QMAKEPATH:+:}$1"
     fi
 }
-envBuildHostHooks+=(qmakePathHook)
+envHostTargetHooks+=(qmakePathHook)
 
 # Propagate any runtime dependency of the building package.
 # Each dependency is propagated to the user environment and as a build
diff --git a/pkgs/development/libraries/qt-5/hooks/qttools-setup-hook.sh b/pkgs/development/libraries/qt-5/hooks/qttools-setup-hook.sh
index 099c0879ed397..0602f8dee6cee 100644
--- a/pkgs/development/libraries/qt-5/hooks/qttools-setup-hook.sh
+++ b/pkgs/development/libraries/qt-5/hooks/qttools-setup-hook.sh
@@ -1 +1,15 @@
-appendToVar qmakeFlags "QMAKE_LRELEASE=@dev@/bin/lrelease"
+# Nowadays lrelease feature in mkspecs of qtbase can automatically find the tool in PATH with qtPrepareTool
+# and process TRANSLATIONS if the pro file has CONFIG+=lrelease in it.
+# But for some reason QMAKE_LRELEASE from qtPrepareTool does not propagate to the pro file itself, and some
+# packages still use QMAKE_LRELEASE directly, so we'll need to pass it explicitly until there's a better
+# mkspecs based solution.
+# NB: this could be non-overridable via qmakeFlags attribute in a package due to hook ordering.
+
+if [[ -z "${__nix_qttoolsHook-}" ]]; then
+    __nix_qttoolsHook=1  # Don't run this hook more than once.
+
+    if ! appendToVar qmakeFlags "QMAKE_LRELEASE=$(PATH="$_PATH" command -v lrelease)" ; then
+        echo "FYI: can't find a runnable lrelease in PATH. If this package doesn't use it than it's perfectly fine."
+        echo "Otherwise you should add qttools to nativeBuildInputs."
+    fi
+fi
diff --git a/pkgs/development/libraries/qt-5/modules/qtbase.nix b/pkgs/development/libraries/qt-5/modules/qtbase.nix
index 0720a23b89363..e98a96903f9ea 100644
--- a/pkgs/development/libraries/qt-5/modules/qtbase.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtbase.nix
@@ -11,11 +11,12 @@
   flex,
   gdb,
   gperf,
-  lndir,
   perl,
   pkg-config,
   python3,
   which,
+  distccMasquerade,
+  qtbase-bootstrap,
   # darwin support
   xcbuild,
 
@@ -56,7 +57,6 @@
   withGtk3 ? false,
   dconf,
   gtk3,
-  withQttranslation ? true,
   qttranslations ? null,
   withLibinput ? false,
   libinput,
@@ -64,27 +64,39 @@
   # options
   libGLSupported ? !stdenv.hostPlatform.isDarwin,
   libGL,
-  # qmake detection for libmysqlclient does not seem to work when cross compiling
-  mysqlSupport ? stdenv.hostPlatform == stdenv.buildPlatform,
+  mysqlSupport ? true,
   libmysqlclient,
   buildExamples ? false,
   buildTests ? false,
   debug ? false,
   developerBuild ? false,
+  bootstrapBuild ? false,
   decryptSslTraffic ? false,
   testers,
-  buildPackages,
 }:
 
 let
   debugSymbols = debug || developerBuild;
+  isCrossBuild = !(lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform);
+
   qtPlatformCross =
-    plat:
-    with plat;
+    with stdenv.hostPlatform;
     if isLinux then
-      "linux-generic-g++"
+      "devices/linux-generic-g++"
+    else if isDarwin then
+      # the logic from the configure script
+      if isAarch64 then "macx-clang-arm64" else "macx-clang-x64"
+    else if isCrossBuild then
+      throw "Please add a qtPlatformCross entry for ${config}"
     else
-      throw "Please add a qtPlatformCross entry for ${plat.config}";
+      null;
+
+  # We need to keep the original mkspec name in the string for pyqt-builder to determine
+  # the target platform.
+  nixCrossConf = builtins.baseNameOf qtPlatformCross + "-nix-cross";
+
+  postFixupPatch = ../${lib.versions.majorMinor version}/qtbase.patch.d/0016-qtbase-cross-build-postFixup.patch;
+
 in
 
 stdenv.mkDerivation (
@@ -141,7 +153,12 @@ stdenv.mkDerivation (
       );
 
       buildInputs = [
+        # We need python3 for hostPlatform to properly patch the shebang of the
+        # mkspecs/features/uikit/devices.py script that we're publishing.
         python3
+        # We need perl for hostPlatform to properly patch shebangs of the
+        # fixqt4headers.pl and syncqt.pl scripts that we're publishing.
+        perl
         at-spi2-core
       ]
       ++ lib.optionals (!stdenv.hostPlatform.isDarwin) (
@@ -156,24 +173,28 @@ stdenv.mkDerivation (
         bison
         flex
         gperf
-        lndir
         perl
         pkg-config
         which
       ]
-      ++ lib.optionals mysqlSupport [ libmysqlclient ]
-      ++ lib.optionals stdenv.hostPlatform.isDarwin [ xcbuild ];
-
-    }
-    // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
-      # `qtbase` expects to find `cc` (with no prefix) in the
-      # `$PATH`, so the following is needed even if
-      # `stdenv.buildPlatform.canExecute stdenv.hostPlatform`
-      depsBuildBuild = [ buildPackages.stdenv.cc ];
-    }
-    // {
+      ++ lib.optionals stdenv.hostPlatform.isDarwin [ xcbuild ]
+      ++ lib.optionals isCrossBuild [
+        # `qtbase` expects to find `cc` (with no prefix) in the `$PATH` for qmake and host_build marked projects.
+        # And we need those to be built for the hostPlatform. So instead of patching configure and mkspeks even
+        # more I'm just masqurading the prefixed tools.
+        # I probably should be using the distccMasquerade._spliced.buildHost here, but it works as it is. It's magic!
+        # Pure wall-of-bash-code-directly-in-derivation-attribute magic!
+        (distccMasquerade.override {
+          gccRaw = stdenv.cc;
+          binutils = stdenv.cc.bintools;
+        })
+      ];
 
-      propagatedNativeBuildInputs = [ lndir ];
+      # qtbase needs a runnable qmake and the accompanying tools to build itself, and there are also packages
+      # out there that use cmake as their main configurator (i.e. don't depend on qmake-the-package) but
+      # still need qmake&co to be available at build time. In fact, cmake scripts provided by qtbase.dev
+      # itself look for those tools.
+      propagatedNativeBuildInputs = lib.optional isCrossBuild qtbase-bootstrap.qmake;
 
       strictDeps = true;
 
@@ -189,6 +210,7 @@ stdenv.mkDerivation (
         "bin"
         "dev"
         "out"
+        "qmake"
       ];
 
       inherit patches;
@@ -219,6 +241,10 @@ stdenv.mkDerivation (
         sed -i 's/NO_DEFAULT_PATH//' src/gui/Qt5GuiConfigExtras.cmake.in
         sed -i '/PATHS.*NO_DEFAULT_PATH/ d' mkspecs/features/data/cmake/Qt5BasicConfig.cmake.in
 
+        # Always build uic and qvkgen for qtbase-bootstrap
+        sed -i '/^TOOLS =/ s/$/ src_tools_qvkgen src_tools_uic/' src/src.pro
+        sed -i '/^SUBDIRS += src_corelib/ s/$/ src_tools_qvkgen src_tools_uic/' src/src.pro
+
         # https://bugs.gentoo.org/803470
         sed -i 's/-lpthread/-pthread/' mkspecs/common/linux.conf src/corelib/configure.json
 
@@ -275,14 +301,22 @@ stdenv.mkDerivation (
         export MAKEFLAGS+=" -j$NIX_BUILD_CORES"
 
         ./bin/syncqt.pl -version $version
+
       ''
-      + lib.optionalString (!stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
-        # QT's configure script will refuse to use pkg-config unless these two environment variables are set
+      # generate a cross compilation config even for native builds so we can pass a natively-built qtbase
+      # as a build dependency for a cross build and to avoid specifying CROSS_COMPILE prefix for qmake later
+      + lib.optionalString (qtPlatformCross != null) ''
+        mkdir mkspecs/${nixCrossConf}
+        echo 'CROSS_COMPILE=${stdenv.hostPlatform.config + "-"}' > mkspecs/${nixCrossConf}/qmake.conf
+        echo 'QMAKE_PKG_CONFIG=''$''$(PKG_CONFIG)' >> mkspecs/${nixCrossConf}/qmake.conf
+        echo 'include(../${qtPlatformCross}/qmake.conf)' >> mkspecs/${nixCrossConf}/qmake.conf
+        echo '#include "../${qtPlatformCross}/qplatformdefs.h"' > mkspecs/${nixCrossConf}/qplatformdefs.h
+
+      ''
+      # QT's configure script will refuse to use pkg-config unless these two environment variables are set
+      + lib.optionalString isCrossBuild ''
         export PKG_CONFIG_SYSROOT_DIR=/
         export PKG_CONFIG_LIBDIR=${lib.getLib pkg-config}/lib
-        echo "QMAKE_LFLAGS=''${LDFLAGS}" >> mkspecs/devices/${qtPlatformCross stdenv.hostPlatform}/qmake.conf
-        echo "QMAKE_CFLAGS=''${CFLAGS}" >> mkspecs/devices/${qtPlatformCross stdenv.hostPlatform}/qmake.conf
-        echo "QMAKE_CXXFLAGS=''${CXXFLAGS}" >> mkspecs/devices/${qtPlatformCross stdenv.hostPlatform}/qmake.conf
       '';
 
       postConfigure = ''
@@ -311,8 +345,6 @@ stdenv.mkDerivation (
         NIX_CFLAGS_COMPILE = toString (
           [
             "-Wno-error=sign-compare" # freetype-2.5.4 changed signedness of some struct fields
-          ]
-          ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
             "-Wno-warn=free-nonheap-object"
             "-Wno-free-nonheap-object"
             "-w"
@@ -330,13 +362,6 @@ stdenv.mkDerivation (
           ]
           ++ lib.optional decryptSslTraffic "-DQT_DECRYPT_SSL_TRAFFIC"
         );
-      }
-      // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
-        NIX_CFLAGS_COMPILE_FOR_BUILD = toString [
-          "-Wno-warn=free-nonheap-object"
-          "-Wno-free-nonheap-object"
-          "-w"
-        ];
       };
 
       prefixKey = "-prefix ";
@@ -347,51 +372,179 @@ stdenv.mkDerivation (
       PSQL_LIBS = lib.optionalString (libpq != null) "-L${libpq}/lib -lpq";
 
     }
-    // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
+    // lib.optionalAttrs isCrossBuild {
       configurePlatforms = [ ];
     }
     // {
       # TODO Remove obsolete and useless flags once the build will be totally mastered
       configureFlags = [
-        "-plugindir $(out)/$(qtPluginPrefix)"
-        "-qmldir $(out)/$(qtQmlPrefix)"
-        "-docdir $(out)/$(qtDocPrefix)"
-
+        # common options for all types of builds
         "-verbose"
         "-confirm-license"
         "-opensource"
 
         "-release"
         "-shared"
-        "-accessibility"
-        "-optimized-qmake"
         # for separateDebugInfo
         "-no-strip"
-        "-system-proxies"
         "-pkg-config"
 
-        "-gui"
-        "-widgets"
-        "-opengl desktop"
+        "-make tools"
+        "-${lib.optionalString (!buildExamples || bootstrapBuild) "no"}make examples"
+        "-${lib.optionalString (!buildTests) "no"}make tests"
+
         "-icu"
         "-L"
         "${icu.out}/lib"
         "-I"
         "${icu.dev}/include"
         "-pch"
+        "-system-zlib"
+        "-L"
+        "${zlib.out}/lib"
+        "-I"
+        "${zlib.dev}/include"
+
       ]
-      ++ lib.optionals (stdenv.hostPlatform != stdenv.buildPlatform) [
-        "-device ${qtPlatformCross stdenv.hostPlatform}"
-        "-device-option CROSS_COMPILE=${stdenv.cc.targetPrefix}"
+      ++ (
+        if stdenv.hostPlatform.isDarwin then
+          [
+            "-no-fontconfig"
+            "-no-framework"
+            "-no-rpath"
+          ]
+        else
+          [
+            "-rpath"
+          ]
+      )
+      # a bare bones build only to get build tools and mkspecs
+      ++ (
+        if bootstrapBuild then
+          [
+            # We probably can go slimmer than this with some patching and/or selective run of Makefiles
+            # but this is already good enough.
+            "-no-gui"
+            "-no-widgets"
+            "-no-feature-sqlmodel"
+            "-no-sql-sqlite"
+            "-no-feature-bearermanagement"
+            "-no-feature-netlistmgr"
+            "-no-feature-networkdiskcache"
+            "-no-feature-networkinterface"
+            "-no-feature-networkproxy"
+            "-no-feature-concurrent"
+            "-no-feature-dnslookup"
+            "-no-feature-dtls"
+            "-no-feature-ftp"
+            "-no-feature-http"
+            "-no-feature-gssapi"
+            "-no-feature-localserver"
+            "-no-feature-ocsp"
+            "-no-feature-socks5"
+            "-no-feature-sspi"
+            "-no-feature-udpsocket"
+          ]
+        else
+          (
+            # regular build, platform-independent options
+            [
+              "-gui"
+              "-widgets"
+              "-opengl desktop"
+              "-accessibility"
+              "-system-proxies"
+              "-make libs"
+
+              "-plugindir $(out)/$(qtPluginPrefix)"
+              "-qmldir $(out)/$(qtQmlPrefix)"
+              "-docdir $(out)/$(qtDocPrefix)"
+
+              "-system-libjpeg"
+              "-L"
+              "${libjpeg.out}/lib"
+              "-I"
+              "${libjpeg.dev}/include"
+              "-system-harfbuzz"
+              "-L"
+              "${harfbuzz.out}/lib"
+              "-I"
+              "${harfbuzz.dev}/include"
+              "-system-pcre"
+              "-openssl-linked"
+              "-L"
+              "${lib.getLib openssl}/lib"
+              "-I"
+              "${openssl.dev}/include"
+              "-system-sqlite"
+              "-${if mysqlSupport then "plugin" else "no"}-sql-mysql"
+              "-${if libpq != null then "plugin" else "no"}-sql-psql"
+              "-system-libpng"
+
+            ]
+            ++ lib.optional (qttranslations != null) [
+              "-translationdir"
+              "${qttranslations}/translations"
+            ]
+            ++ (
+              # regular build, Darwin options
+              # regular build, other Unixes options
+              [
+                "-xcb"
+                "-qpa xcb"
+                "-L"
+                "${libX11.out}/lib"
+                "-I"
+                "${libX11.out}/include"
+                "-L"
+                "${libXext.out}/lib"
+                "-I"
+                "${libXext.out}/include"
+                "-L"
+                "${libXrender.out}/lib"
+                "-I"
+                "${libXrender.out}/include"
+
+                "-${lib.optionalString (cups == null) "no-"}cups"
+                "-dbus-linked"
+                "-glib"
+              ]
+              ++ lib.optional withGtk3 "-gtk"
+              ++ lib.optional withLibinput "-libinput"
+              ++ [
+                "-inotify"
+              ]
+              ++ lib.optionals (cups != null) [
+                "-L"
+                "${cups.lib}/lib"
+                "-I"
+                "${cups.dev}/include"
+              ]
+              ++ lib.optionals mysqlSupport [
+                "-L"
+                "${libmysqlclient}/lib/mysql"
+                "-I"
+                "${libmysqlclient}/include/mysql"
+              ]
+
+            )
+          )
+      )
+
+      # cross compilation options
+      ++ lib.optionals isCrossBuild [
+        "-xplatform ${nixCrossConf}"
+        "-external-hostbindir ${qtbase-bootstrap.qmake}/bin"
       ]
+
+      # debugging options
       ++ lib.optional debugSymbols "-debug"
       ++ lib.optionals developerBuild [
         "-developer-build"
         "-no-warnings-are-errors"
       ]
-      ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
-        "-no-warnings-are-errors"
-      ]
+
+      # CPU features support
       ++ (
         if (!stdenv.hostPlatform.isx86_64) then
           [
@@ -411,97 +564,27 @@ stdenv.mkDerivation (
       ++ [
         "-no-mips_dsp"
         "-no-mips_dspr2"
-      ]
-      ++ [
-        "-system-zlib"
-        "-L"
-        "${zlib.out}/lib"
-        "-I"
-        "${zlib.dev}/include"
-        "-system-libjpeg"
-        "-L"
-        "${libjpeg.out}/lib"
-        "-I"
-        "${libjpeg.dev}/include"
-        "-system-harfbuzz"
-        "-L"
-        "${harfbuzz.out}/lib"
-        "-I"
-        "${harfbuzz.dev}/include"
-        "-system-pcre"
-        "-openssl-linked"
-        "-L"
-        "${lib.getLib openssl}/lib"
-        "-I"
-        "${openssl.dev}/include"
-        "-system-sqlite"
-        "-${if mysqlSupport then "plugin" else "no"}-sql-mysql"
-        "-${if libpq != null then "plugin" else "no"}-sql-psql"
-        "-system-libpng"
-
-        "-make libs"
-        "-make tools"
-        "-${lib.optionalString (!buildExamples) "no"}make examples"
-        "-${lib.optionalString (!buildTests) "no"}make tests"
-      ]
-      ++ (
-        if stdenv.hostPlatform.isDarwin then
-          [
-            "-no-fontconfig"
-            "-no-framework"
-            "-no-rpath"
-          ]
-        else
-          [
-            "-rpath"
-          ]
-          ++ [
-            "-xcb"
-            "-qpa xcb"
-            "-L"
-            "${libX11.out}/lib"
-            "-I"
-            "${libX11.out}/include"
-            "-L"
-            "${libXext.out}/lib"
-            "-I"
-            "${libXext.out}/include"
-            "-L"
-            "${libXrender.out}/lib"
-            "-I"
-            "${libXrender.out}/include"
-
-            "-${lib.optionalString (cups == null) "no-"}cups"
-            "-dbus-linked"
-            "-glib"
-          ]
-          ++ lib.optional withGtk3 "-gtk"
-          ++ lib.optional withLibinput "-libinput"
-          ++ [
-            "-inotify"
-          ]
-          ++ lib.optionals (cups != null) [
-            "-L"
-            "${cups.lib}/lib"
-            "-I"
-            "${cups.dev}/include"
-          ]
-          ++ lib.optionals mysqlSupport [
-            "-L"
-            "${libmysqlclient}/lib"
-            "-I"
-            "${libmysqlclient}/include"
-          ]
-          ++ lib.optional (withQttranslation && (qttranslations != null)) [
-            # depends on x11
-            "-translationdir"
-            "${qttranslations}/translations"
-          ]
-      );
+      ];
 
       # Move selected outputs.
+      # I don't want to patch moveQtDevTools to support qmake output, so here's a bit of moving binaries around
       postInstall = ''
         moveToOutput "mkspecs" "$dev"
+
+        # Move development tools to $dev and update paths to them in mkspecs
+        moveQtDevTools
+
+        # Move all binaries to $qmake
+        mkdir -p "$qmake/bin"
+        mv "$dev"/bin/* "$qmake/bin/"
+        moveToOutput "bin" "$qmake"
+        patchShebangs --host --update "$qmake"
+
+        patchShebangs --host --update "$dev"
+
+        # Symlinks from $dev to $qmake for backward compatibility
+        mkdir -p "$dev/bin"
+        lndir "$qmake/bin" "$dev/bin"
       '';
 
       devTools = [
@@ -519,13 +602,17 @@ stdenv.mkDerivation (
       postFixup = ''
         # Don't retain build-time dependencies like gdb.
         sed '/QMAKE_DEFAULT_.*DIRS/ d' -i $dev/mkspecs/qconfig.pri
+
+        # Don't propagate nativeBuildInputs
+        sed '/HOST_QT_TOOLS/ d' -i $dev/mkspecs/qmodule.pri
+        sed '/PKG_CONFIG_LIBDIR/ d' -i $dev/mkspecs/qconfig.pri
+
+        # Dynamically detect cross-compilation. This patch breaks the build of qtbase itself, so we need to appy it late.
+        patch -p1 -d $dev < ${postFixupPatch}
+
         fixQtModulePaths "''${!outputDev}/mkspecs/modules"
         fixQtBuiltinPaths "''${!outputDev}" '*.pr?'
 
-        # Move development tools to $dev
-        moveQtDevTools
-        moveToOutput bin "$dev"
-
         # fixup .pc file (where to find 'moc' etc.)
         sed -i "$dev/lib/pkgconfig/Qt5Core.pc" \
           -e "/^host_bins=/ c host_bins=$dev/bin"
diff --git a/pkgs/development/libraries/qt-5/modules/qtdeclarative.nix b/pkgs/development/libraries/qt-5/modules/qtdeclarative.nix
index ad0465417dffe..3a31ebf84b8a9 100644
--- a/pkgs/development/libraries/qt-5/modules/qtdeclarative.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtdeclarative.nix
@@ -1,17 +1,23 @@
 {
+  lib,
+  stdenv,
   qtModule,
   python3,
   qtbase,
-  qtsvg,
+  qtdeclarative,
 }:
 
+let
+  isCrossBuild = !(lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform);
+in
+
 qtModule {
   pname = "qtdeclarative";
-  propagatedBuildInputs = [
-    qtbase
-    qtsvg
-  ];
+  buildInputs = [ qtbase ];
   nativeBuildInputs = [ python3 ];
+  # We need a runnable qmlcachegen to build qtdeclarative itself, and some dependers
+  # of this package also expect to get runnable tools with it.
+  propagatedNativeBuildInputs = lib.optional isCrossBuild qtdeclarative;
   outputs = [
     "out"
     "dev"
diff --git a/pkgs/development/libraries/qt-5/modules/qtdoc.nix b/pkgs/development/libraries/qt-5/modules/qtdoc.nix
index 93620e42667e0..48b61f33ce7c6 100644
--- a/pkgs/development/libraries/qt-5/modules/qtdoc.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtdoc.nix
@@ -1,7 +1,14 @@
-{ qtModule, qtdeclarative }:
+{
+  qtModule,
+  qtbase,
+  qtdeclarative,
+}:
 
 qtModule {
   pname = "qtdoc";
-  propagatedBuildInputs = [ qtdeclarative ];
+  propagatedBuildInputs = [
+    qtbase
+    qtdeclarative
+  ];
   outputs = [ "out" ];
 }
diff --git a/pkgs/development/libraries/qt-5/modules/qtgraphicaleffects.nix b/pkgs/development/libraries/qt-5/modules/qtgraphicaleffects.nix
index df1c9bf14884c..686775c9fc749 100644
--- a/pkgs/development/libraries/qt-5/modules/qtgraphicaleffects.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtgraphicaleffects.nix
@@ -1,8 +1,15 @@
-{ qtModule, qtdeclarative }:
+{
+  qtModule,
+  qtbase,
+  qtdeclarative,
+}:
 
 qtModule {
   pname = "qtgraphicaleffects";
-  propagatedBuildInputs = [ qtdeclarative ];
+  propagatedBuildInputs = [
+    qtbase
+    qtdeclarative
+  ];
   outputs = [
     "out"
     "dev"
diff --git a/pkgs/development/libraries/qt-5/modules/qtmultimedia.nix b/pkgs/development/libraries/qt-5/modules/qtmultimedia.nix
index d54bbd0a9284c..b4ff43033bc27 100644
--- a/pkgs/development/libraries/qt-5/modules/qtmultimedia.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtmultimedia.nix
@@ -6,8 +6,7 @@
   qtdeclarative,
   pkg-config,
   alsa-lib,
-  gstreamer,
-  gst-plugins-base,
+  gst_all_1,
   libpulseaudio,
   wayland,
 }:
@@ -19,16 +18,18 @@ qtModule {
     qtdeclarative
   ];
   nativeBuildInputs = [ pkg-config ];
-  buildInputs = [
-    gstreamer
-    gst-plugins-base
-  ]
-  # https://github.com/NixOS/nixpkgs/pull/169336 regarding libpulseaudio
-  ++ lib.optionals stdenv.hostPlatform.isLinux [
-    libpulseaudio
-    alsa-lib
-    wayland
-  ];
+  buildInputs =
+    with gst_all_1;
+    [
+      gstreamer
+      gst-plugins-base
+    ]
+    # https://github.com/NixOS/nixpkgs/pull/169336 regarding libpulseaudio
+    ++ lib.optionals stdenv.hostPlatform.isLinux [
+      libpulseaudio
+      alsa-lib
+      wayland
+    ];
   outputs = [
     "bin"
     "dev"
diff --git a/pkgs/development/libraries/qt-5/modules/qtquickcontrols.nix b/pkgs/development/libraries/qt-5/modules/qtquickcontrols.nix
index 3b78a2a6c87ed..c2770b2209650 100644
--- a/pkgs/development/libraries/qt-5/modules/qtquickcontrols.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtquickcontrols.nix
@@ -1,6 +1,13 @@
-{ qtModule, qtdeclarative }:
+{
+  qtModule,
+  qtbase,
+  qtdeclarative,
+}:
 
 qtModule {
   pname = "qtquickcontrols";
-  propagatedBuildInputs = [ qtdeclarative ];
+  propagatedBuildInputs = [
+    qtbase
+    qtdeclarative
+  ];
 }
diff --git a/pkgs/development/libraries/qt-5/modules/qtquickcontrols2.nix b/pkgs/development/libraries/qt-5/modules/qtquickcontrols2.nix
index 041a001743747..8abdeda55dc3f 100644
--- a/pkgs/development/libraries/qt-5/modules/qtquickcontrols2.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtquickcontrols2.nix
@@ -1,8 +1,15 @@
-{ qtModule, qtdeclarative }:
+{
+  qtModule,
+  qtbase,
+  qtdeclarative,
+}:
 
 qtModule {
   pname = "qtquickcontrols2";
-  propagatedBuildInputs = [ qtdeclarative ];
+  propagatedBuildInputs = [
+    qtbase
+    qtdeclarative
+  ];
   outputs = [
     "out"
     "dev"
diff --git a/pkgs/development/libraries/qt-5/modules/qtsvg.nix b/pkgs/development/libraries/qt-5/modules/qtsvg.nix
index 5800a959d8d11..59e7f1e243796 100644
--- a/pkgs/development/libraries/qt-5/modules/qtsvg.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtsvg.nix
@@ -2,7 +2,7 @@
 
 qtModule {
   pname = "qtsvg";
-  propagatedBuildInputs = [ qtbase ];
+  buildInputs = [ qtbase ];
   outputs = [
     "out"
     "dev"
diff --git a/pkgs/development/libraries/qt-5/modules/qttools.nix b/pkgs/development/libraries/qt-5/modules/qttools.nix
index 438300124964b..d4bbb7da8d209 100644
--- a/pkgs/development/libraries/qt-5/modules/qttools.nix
+++ b/pkgs/development/libraries/qt-5/modules/qttools.nix
@@ -4,10 +4,15 @@
   lib,
   qtbase,
   qtdeclarative,
+  qttools,
   replaceVars,
   llvmPackages,
 }:
 
+let
+  isCrossBuild = !(lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform);
+in
+
 qtModule {
   pname = "qttools";
 
@@ -20,13 +25,14 @@ qtModule {
   buildInputs = with llvmPackages; [
     libclang
     libllvm
-  ];
-
-  propagatedBuildInputs = [
     qtbase
     qtdeclarative
   ];
 
+  # We don't need this to build qttools itself, only for the packages that include qttools
+  # in their buildInputs and expect to get not only libs but also runnable tools.
+  propagatedNativeBuildInputs = lib.optional isCrossBuild qttools;
+
   patches = [
     # fixQtBuiltinPaths overwrites builtin paths we should keep
     (replaceVars ./qttools-QT_HOST_DATA-refs.patch {
@@ -38,6 +44,9 @@ qtModule {
     })
   ];
 
+  # Bootstrap build produces no out, and that makes nix unhappy and results in an unannotated failure for remote builds.
+  postFixup = "[ -e $out ] || mkdir $out";
+
   devTools = [
     "bin/qcollectiongenerator"
     "bin/linguist"
diff --git a/pkgs/development/libraries/qt-5/modules/qttranslations.nix b/pkgs/development/libraries/qt-5/modules/qttranslations.nix
index bcd52cdc4a8f6..d3891628e87de 100644
--- a/pkgs/development/libraries/qt-5/modules/qttranslations.nix
+++ b/pkgs/development/libraries/qt-5/modules/qttranslations.nix
@@ -1,7 +1,23 @@
-{ qtModule, qttools }:
+{
+  qtModule,
+  stdenv,
+  qtbase-bootstrap,
+  qttools-bootstrap,
+  buildPackages,
+}:
 
-qtModule {
-  pname = "qttranslations";
-  nativeBuildInputs = [ qttools ];
-  outputs = [ "out" ];
-}
+# I don't want to bother with cross compilation support for qttranslations
+# as the outputs are identical with a native-built one. It will require a small
+# fiddling with a native-built qtbase-bootstrap in buildInputs (it is there only
+# for a few configs in mkspecs) or an additional individual build of qtbase/mkspecs
+# just for the sake of this package. There's really just no point in it.
+if stdenv.hostPlatform != stdenv.buildPlatform then
+  buildPackages.qt5.qttranslations
+
+else
+  qtModule {
+    pname = "qttranslations";
+    buildInputs = [ qtbase-bootstrap.dev ];
+    nativeBuildInputs = [ qttools-bootstrap ];
+    outputs = [ "out" ];
+  }
diff --git a/pkgs/development/libraries/qt-5/modules/qtwayland.nix b/pkgs/development/libraries/qt-5/modules/qtwayland.nix
index 674ab85bea617..f6d0cb8e39107 100644
--- a/pkgs/development/libraries/qt-5/modules/qtwayland.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtwayland.nix
@@ -1,24 +1,32 @@
 {
   qtModule,
   qtbase,
-  qtquickcontrols,
+  qtdeclarative,
+  qtwayland,
   wayland,
   wayland-scanner,
   pkg-config,
+  buildPackages,
+  stdenv,
   lib,
 }:
 
+let
+  isCrossBuild = !(lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform);
+in
+
 qtModule {
   pname = "qtwayland";
-  propagatedBuildInputs = [
-    qtbase
-    qtquickcontrols
+  propagatedBuildInputs = [ qtbase ];
+  buildInputs = [
+    wayland
+    qtdeclarative
   ];
-  buildInputs = [ wayland ];
   nativeBuildInputs = [
     pkg-config
     wayland-scanner
-  ];
+  ]
+  ++ lib.optional isCrossBuild qtwayland.bin;
   outputs = [
     "out"
     "dev"
@@ -30,5 +38,6 @@ qtModule {
     # context).
     ./qtwayland-app_id.patch
   ];
+  disallowedReferences = lib.optional isCrossBuild buildPackages.qt5.qtwayland.bin;
   meta.badPlatforms = lib.platforms.darwin;
 }
diff --git a/pkgs/development/libraries/qt-5/modules/qtwebchannel.nix b/pkgs/development/libraries/qt-5/modules/qtwebchannel.nix
index c92f6d56e13b3..d105645342539 100644
--- a/pkgs/development/libraries/qt-5/modules/qtwebchannel.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtwebchannel.nix
@@ -1,6 +1,4 @@
 {
-  lib,
-  stdenv,
   qtModule,
   qtbase,
   qtdeclarative,
@@ -15,6 +13,6 @@ qtModule {
   outputs = [
     "out"
     "dev"
-  ]
-  ++ lib.optionals (stdenv.hostPlatform == stdenv.buildPlatform) [ "bin" ];
+    "bin"
+  ];
 }
diff --git a/pkgs/development/libraries/qt-5/modules/qtwebengine.nix b/pkgs/development/libraries/qt-5/modules/qtwebengine.nix
index 61aac879b93fd..11cfc9435b942 100644
--- a/pkgs/development/libraries/qt-5/modules/qtwebengine.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtwebengine.nix
@@ -6,19 +6,17 @@
   qtwebchannel,
   fetchpatch,
   fetchpatch2,
+  srcs,
 
   bison,
   flex,
   gperf,
   ninja,
   pkg-config,
-  python,
   which,
   nodejs,
   perl,
   buildPackages,
-  pkgsBuildTarget,
-  pkgsBuildBuild,
 
   libxdamage,
   libxcomposite,
@@ -38,24 +36,25 @@
   zlib,
   minizip,
   libjpeg,
+  openjpeg,
   libpng,
   libtiff,
   libwebp,
   libopus,
-  jsoncpp,
-  protobuf,
   libvpx,
   srtp,
   snappy,
   nss,
   libevent,
+  lcms2,
+  libxml2,
+  libxslt,
   alsa-lib,
   pulseaudio,
   libcap,
   pciutils,
   systemd,
   enableProprietaryCodecs ? true,
-  gn,
   cctools,
   cups,
   bootstrap_cmds,
@@ -69,27 +68,56 @@
   pipewireSupport ? stdenv.hostPlatform.isLinux,
   pipewire,
   postPatch ? "",
-  nspr,
-  lndir,
 }:
 
 let
-  # qtwebengine expects to find an executable in $PATH which runs on
-  # the build platform yet knows about the host `.pc` files.  Most
-  # configury allows setting $PKG_CONFIG to point to an
-  # arbitrarily-named script which serves this purpose; however QT
-  # insists that it is named `pkg-config` with no target prefix.  So
-  # we re-wrap the host platform's pkg-config.
-  pkg-config-wrapped-without-prefix = stdenv.mkDerivation {
-    name = "pkg-config-wrapper-without-target-prefix";
-    dontUnpack = true;
-    dontBuild = true;
-    installPhase = ''
-      mkdir -p $out/bin
-      ln -s '${buildPackages.pkg-config}/bin/${buildPackages.pkg-config.targetPrefix}pkg-config' $out/bin/pkg-config
-    '';
-  };
+  isCrossBuild = !(lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform);
+
+  # qtwebengine requires its own very particular specially patched for qt version of gn
+  gnQtWebengine =
+    with srcs.qtwebengine;
+    buildPackages.gn.overrideAttrs {
+      pname = "gn-qtwebengine";
+      inherit src version;
+      sourceRoot = "${src.name}/src/3rdparty/gn";
+      configurePhase = ''
+        # using $CXX as ld because the script uses --gc-sections, and ld doesn't recognize it.
+        # on a related note, here we can see as QT developers intentionally de-standardize build tools:
+        # https://github.com/qt/qtwebengine-chromium/commit/0e7e61966f9215babb0d4b32d97b9c0b73db1ca9
+        python build/gen.py --no-last-commit-position --cc $CC --cxx $CXX --ld $CXX --ar $AR
+      '';
+      buildPhase = ''
+        ninja -j $NIX_BUILD_CORES -C out gn
+      '';
+    };
 
+  # Overriding stdenv seems to be a common thing for qt5 scope, so I'm using the
+  # "__spliced or" construction here instead of pkgsBuildBuild.
+  stdenvForBuildPlatform = stdenv.__spliced.buildBuild or stdenv;
+
+  cflagsForPlatform =
+    stdenv:
+    toString (
+      [ "-w " ]
+      ++ lib.optionals stdenv.cc.isGNU [
+        # with gcc8, -Wclass-memaccess became part of -Wall and this exceeds the logging limit
+        "-Wno-class-memaccess"
+      ]
+      ++ lib.optionals (stdenv.hostPlatform.gcc.arch or "" == "sandybridge") [
+        # it fails when compiled with -march=sandybridge https://github.com/NixOS/nixpkgs/pull/59148#discussion_r276696940
+        # TODO: investigate and fix properly
+        "-march=westmere"
+      ]
+      ++ lib.optionals stdenv.cc.isClang [
+        "-Wno-elaborated-enum-base"
+        # 5.15.17: need to silence these two warnings
+        # https://trac.macports.org/ticket/70850
+        "-Wno-enum-constexpr-conversion"
+        "-Wno-unused-but-set-variable"
+        # Clang 19
+        "-Wno-error=missing-template-arg-list-after-template-kw"
+      ]
+    );
 in
 
 qtModule (
@@ -101,23 +129,52 @@ qtModule (
       gperf
       ninja
       pkg-config
-      (python.withPackages (ps: [ ps.html5lib ]))
+      (buildPackages.python3.withPackages (ps: [ ps.html5lib ]))
       which
-      gn
+      gnQtWebengine
       nodejs
     ]
-    ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
-      perl
-      lndir
-      (lib.getDev pkgsBuildTarget.targetPackages.qt5.qtbase)
-      pkgsBuildBuild.pkg-config
-      (lib.getDev pkgsBuildTarget.targetPackages.qt5.qtquickcontrols)
-      pkg-config-wrapped-without-prefix
-    ]
     ++ lib.optional stdenv.hostPlatform.isDarwin [
       bootstrap_cmds
       xcbuild
+
+      # FIXME These dependencies shouldn't be needed but can't find a way
+      # around it. Chromium pulls this in while bootstrapping GN.
+      cctools.libtool
+
+      # `sw_vers` is used by `src/3rdparty/chromium/build/config/mac/sdk_info.py`
+      # to get some information about the host platform.
+      (writeScriptBin "sw_vers" ''
+        #!${stdenv.shell}
+
+        while [ $# -gt 0 ]; do
+          case "$1" in
+            -buildVersion) echo "17E199";;
+          *) break ;;
+
+          esac
+          shift
+        done
+      '')
     ];
+
+    # For "host" builds in chromium. Only cc in depsBuildBuild will produce
+    # _FOR_BUILD env variables that are used in qtwebengine-cross-build.patch.
+    depsBuildBuild = [
+      stdenvForBuildPlatform.cc
+      pkg-config
+      zlib
+      nss
+      icu
+      # apparently chromium doesn't care if these deps are non-functional on the buildPlatform
+      # but build fails if pkg-config can't find them
+      libjpeg
+      libpng
+      libwebp
+      freetype
+      harfbuzz
+    ];
+    strictDeps = true;
     doCheck = true;
     outputs = [
       "bin"
@@ -224,21 +281,45 @@ qtModule (
 
       # Fix the build with gperf ≥ 3.2 and Clang 19.
       ./qtwebengine-gperf-3.2.patch
+
+      # Support building with gcc15
+      (fetchpatch2 {
+        url = "https://salsa.debian.org/qt-kde-team/qt/qtwebengine/-/raw/451b2e7a6a0ac2c6eb409b4e2c03dada141bcd7f/debian/patches/gcc-15.patch";
+        hash = "sha256-nOGntSYDwyYXZYb1/VQMJQDfvn2KbN5/Ok4rs/ZabdQ=";
+      })
+
+      # support for building with python 3.12
+      (fetchpatch2 {
+        url = "https://salsa.debian.org/qt-kde-team/qt/qtwebengine/-/raw/313423e0178cee6eb9419c5803b982df2a71d689/debian/patches/python3.12-six.patch";
+        hash = "sha256-gjc9sOPbcyHtJWnSHpkpupY6dIAODO20tiaTEtAfFr0=";
+      })
+
+      # Build with C++17, which is required by ICU 75
+      (fetchpatch2 {
+        url = "https://salsa.debian.org/qt-kde-team/qt/qtwebengine/-/raw/313423e0178cee6eb9419c5803b982df2a71d689/debian/patches/build-with-c++17.patch";
+        hash = "sha256-1fhkj50radAc3uG386UnS735+LRe0Xs8jQOJtMqE7hQ=";
+      })
+
+      # Use system openjpeg
+      (fetchpatch2 {
+        url = "https://salsa.debian.org/qt-kde-team/qt/qtwebengine/-/raw/313423e0178cee6eb9419c5803b982df2a71d689/debian/patches/system-openjpeg2.patch";
+        hash = "sha256-H3WwC40t0FRMGf1K2aXucrQjynMU/U/14goB4HK9/KM=";
+      })
+
+      # Use system lcms2
+      (fetchpatch2 {
+        url = "https://salsa.debian.org/qt-kde-team/qt/qtwebengine/-/raw/313423e0178cee6eb9419c5803b982df2a71d689/debian/patches/system-lcms2.patch";
+        hash = "sha256-ccEbt5T54uXTV1pJnHI12NfYJ+QdUSUJFj0xcKcmtIA=";
+      })
     ];
 
     postPatch = ''
       # Patch Chromium build tools
       (
-        cd src/3rdparty/chromium;
+        # Force configure to accept qtwebengine's own version of gn when passed from outside
+        substituteInPlace configure.pri --replace 'qtLog("Gn version too old")' 'return(true)'
 
-        patch -p1 < ${
-          (fetchpatch {
-            # support for building with python 3.12
-            name = "python312-six.patch";
-            url = "https://gitlab.archlinux.org/archlinux/packaging/packages/qt5-webengine/-/raw/6b0c0e76e0934db2f84be40cb5978cee47266e78/python3.12-six.patch";
-            hash = "sha256-YgP9Sq5+zTC+U7+0hQjZokwb+fytk0UEIJztUXFhTkI=";
-          })
-        }
+        cd src/3rdparty/chromium;
 
         # Manually fix unsupported shebangs
         substituteInPlace third_party/harfbuzz-ng/src/src/update-unicode-tables.make \
@@ -282,56 +363,24 @@ qtModule (
     + postPatch;
 
     env = {
-      NIX_CFLAGS_COMPILE = toString (
-        lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
-          "-w "
-        ]
-        ++ lib.optionals stdenv.cc.isGNU [
-          # with gcc8, -Wclass-memaccess became part of -Wall and this exceeds the logging limit
-          "-Wno-class-memaccess"
-        ]
-        ++ lib.optionals (stdenv.hostPlatform.gcc.arch or "" == "sandybridge") [
-          # it fails when compiled with -march=sandybridge https://github.com/NixOS/nixpkgs/pull/59148#discussion_r276696940
-          # TODO: investigate and fix properly
-          "-march=westmere"
-        ]
-        ++ lib.optionals stdenv.cc.isClang [
-          "-Wno-elaborated-enum-base"
-          # 5.15.17: need to silence these two warnings
-          # https://trac.macports.org/ticket/70850
-          "-Wno-enum-constexpr-conversion"
-          "-Wno-unused-but-set-variable"
-          # Clang 19
-          "-Wno-error=missing-template-arg-list-after-template-kw"
-        ]
-      );
-    }
-    // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
-      NIX_CFLAGS_LINK = "-Wl,--no-warn-search-mismatch";
-      "NIX_CFLAGS_LINK_${buildPackages.stdenv.cc.suffixSalt}" = "-Wl,--no-warn-search-mismatch";
+      NIX_CFLAGS_COMPILE = cflagsForPlatform stdenv;
+      NIX_CFLAGS_COMPILE_FOR_BUILD = cflagsForPlatform stdenvForBuildPlatform;
     };
 
     preConfigure = ''
       export NINJAFLAGS=-j$NIX_BUILD_CORES
-
-      if [ -d "$PWD/tools/qmake" ]; then
-          QMAKEPATH="$PWD/tools/qmake''${QMAKEPATH:+:}$QMAKEPATH"
-      fi
-    ''
-    + lib.optionalString (stdenv.hostPlatform != stdenv.buildPlatform) ''
-      export QMAKE_CC=$CC
-      export QMAKE_CXX=$CXX
-      export QMAKE_LINK=$CXX
-      export QMAKE_AR=$AR
     '';
 
     qmakeFlags = [
       "--"
-      "-system-ffmpeg"
+      "-feature-webengine-system-gn"
+      "-webengine-icu"
     ]
-    ++ lib.optional (
-      pipewireSupport && stdenv.buildPlatform == stdenv.hostPlatform
-    ) "-webengine-webrtc-pipewire"
+    # webengine-embedded-build disables WebRTC, "Printing and PDF" and breaks PyQtWebEngine build.
+    # It is automatically switched on for cross compilation. We probably always want it disabled.
+    ++ lib.optional stdenv.hostPlatform.isLinux "-no-webengine-embedded-build"
+    ++ lib.optional (ffmpeg_7 != null) "-webengine-ffmpeg"
+    ++ lib.optional (pipewireSupport && !isCrossBuild) "-webengine-webrtc-pipewire"
     ++ lib.optional enableProprietaryCodecs "-proprietary-codecs";
 
     propagatedBuildInputs = [
@@ -339,9 +388,14 @@ qtModule (
       qtquickcontrols
       qtlocation
       qtwebchannel
+    ];
 
+    # Optional dependency on system-provided re2 library is not used here because it activates
+    # some broken code paths in chromium.
+    buildInputs = [
       # Image formats
       libjpeg
+      openjpeg
       libpng
       libtiff
       libwebp
@@ -356,18 +410,20 @@ qtModule (
       # Text rendering
       harfbuzz
       icu
+      freetype
 
       libevent
       ffmpeg_7
+
+      lcms2
+
+      snappy
+      minizip
+      zlib
     ]
     ++ lib.optionals (!stdenv.hostPlatform.isDarwin) [
       dbus
-      zlib
-      minizip
-      snappy
       nss
-      protobuf
-      jsoncpp
 
       # Audio formats
       alsa-lib
@@ -375,11 +431,17 @@ qtModule (
 
       # Text rendering
       fontconfig
-      freetype
 
       libcap
       pciutils
 
+      # there's an explicit check for LIBXML_ICU_ENABLED at configuraion time
+      # FIXME: still doesn't work because of the propagation of non-icu libxml2
+      # from qtbase. Not sure what is the right move here.
+      # FIXME: those could also be used on Darwin if we fix https://github.com/NixOS/nixpkgs/issues/272383
+      (libxml2.override { icuSupport = true; })
+      libxslt
+
       # X11 libs
       xrandr
       libXScrnSaver
@@ -393,39 +455,28 @@ qtModule (
       libxkbfile
 
     ]
-    ++ lib.optionals pipewireSupport [
+    ++ lib.optionals (pipewireSupport && !isCrossBuild) [
       # Pipewire
       pipewire
     ]
+    ++ lib.optionals stdenv.hostPlatform.isDarwin [
+      # FIXME This dependency shouldn't be needed but can't find a way
+      # around it. Chromium pulls this in while bootstrapping GN.
+      cctools.libtool
 
-    # FIXME These dependencies shouldn't be needed but can't find a way
-    # around it. Chromium pulls this in while bootstrapping GN.
-    ++ lib.optionals stdenv.hostPlatform.isDarwin [ cctools.libtool ];
-
-    buildInputs = lib.optionals stdenv.hostPlatform.isDarwin [
       cups
-
-      # `sw_vers` is used by `src/3rdparty/chromium/build/config/mac/sdk_info.py`
-      # to get some information about the host platform.
-      (writeScriptBin "sw_vers" ''
-        #!${stdenv.shell}
-
-        while [ $# -gt 0 ]; do
-          case "$1" in
-            -buildVersion) echo "17E199";;
-          *) break ;;
-
-          esac
-          shift
-        done
-      '')
     ];
 
+    # to get progress output in `nix-build` and `nix build -L`
+    preBuild = ''
+      export TERM=dumb
+    '';
+
     dontUseNinjaBuild = true;
     dontUseNinjaInstall = true;
 
     postInstall =
-      lib.optionalString (stdenv.buildPlatform != stdenv.hostPlatform) ''
+      lib.optionalString isCrossBuild ''
         mkdir -p $out/libexec
       ''
       + lib.optionalString stdenv.hostPlatform.isLinux ''
@@ -506,18 +557,7 @@ qtModule (
     };
 
   }
-  // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
+  // lib.optionalAttrs isCrossBuild {
     configurePlatforms = [ ];
-    # to get progress output in `nix-build` and `nix build -L`
-    preBuild = ''
-      export TERM=dumb
-    '';
-    depsBuildBuild = [
-      pkgsBuildBuild.stdenv
-      zlib
-      nss
-      nspr
-    ];
-
   }
 )
diff --git a/pkgs/development/libraries/qt-5/modules/qtwebkit.nix b/pkgs/development/libraries/qt-5/modules/qtwebkit.nix
index bf4282fffef0f..e3f9c6bd242cd 100644
--- a/pkgs/development/libraries/qt-5/modules/qtwebkit.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtwebkit.nix
@@ -26,22 +26,10 @@
   pkg-config,
   python3,
   ruby,
+  hyphen,
+  woff2,
 }:
 
-let
-  hyphen = stdenv.mkDerivation rec {
-    pname = "hyphen";
-    version = "2.8.8";
-    src = fetchurl {
-      url = "http://dev-www.libreoffice.org/src/5ade6ae2a99bc1e9e57031ca88d36dad-hyphen-${version}.tar.gz";
-      sha256 = "304636d4eccd81a14b6914d07b84c79ebb815288c76fe027b9ebff6ff24d5705";
-    };
-    postPatch = ''
-      patchShebangs tests
-    '';
-    buildInputs = [ perl ];
-  };
-in
 qtModule {
   pname = "qtwebkit";
   propagatedBuildInputs = [
@@ -62,6 +50,7 @@ qtModule {
     gst_all_1.gstreamer
     gst_all_1.gst-plugins-base
     hyphen
+    woff2
   ];
   nativeBuildInputs = [
     bison
diff --git a/pkgs/development/libraries/qt-5/qtModule.nix b/pkgs/development/libraries/qt-5/qtModule.nix
index 04daeb222aef5..c90a46c8128a5 100644
--- a/pkgs/development/libraries/qt-5/qtModule.nix
+++ b/pkgs/development/libraries/qt-5/qtModule.nix
@@ -1,13 +1,12 @@
 {
   lib,
   stdenv,
-  buildPackages,
   mkDerivation,
   perl,
   qmake,
   patches,
   srcs,
-  pkgsHostTarget,
+  qtbase-bootstrap,
 }:
 
 let
@@ -30,23 +29,14 @@ mkDerivation (
 
     buildInputs = args.buildInputs or [ ];
 
-    nativeBuildInputs =
-      (args.nativeBuildInputs or [ ])
-      ++ [
-        perl
-        qmake
-      ]
-      ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
-        pkgsHostTarget.qt5.qtbase.dev
-      ];
+    nativeBuildInputs = (args.nativeBuildInputs or [ ]) ++ [
+      perl
+      qmake
+    ];
+
     propagatedBuildInputs =
       (lib.warnIf (args ? qtInputs) "qt5.qtModule's qtInputs argument is deprecated" args.qtInputs or [ ])
       ++ (args.propagatedBuildInputs or [ ]);
-  }
-  // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
-    depsBuildBuild = [ buildPackages.stdenv.cc ] ++ (args.depsBuildBuild or [ ]);
-  }
-  // {
 
     outputs =
       args.outputs or [
@@ -64,6 +54,7 @@ mkDerivation (
       ${args.preConfigure or ""}
 
       fixQtBuiltinPaths . '*.pr?'
+      fixQtBuiltinPaths . '*.cmake.in'
     ''
     +
       lib.optionalString (builtins.compareVersions "5.15.0" version <= 0)
@@ -102,6 +93,8 @@ mkDerivation (
       ${args.postFixup or ""}
     '';
 
+    disallowedReferences = (args.disallowedReferences or [ ]) ++ [ qtbase-bootstrap.qmake ];
+
     meta = {
       homepage = "https://www.qt.io";
       description = "Cross-platform application framework for C++";
diff --git a/pkgs/development/python-modules/pyqt/5.x.nix b/pkgs/development/python-modules/pyqt/5.x.nix
index 66138c7cb5a12..cfd31b9d3fbf9 100644
--- a/pkgs/development/python-modules/pyqt/5.x.nix
+++ b/pkgs/development/python-modules/pyqt/5.x.nix
@@ -7,7 +7,6 @@
   fetchPypi,
   pkg-config,
   dbus,
-  lndir,
   dbus-python,
   sip,
   pyqt5-sip,
@@ -22,7 +21,6 @@
   withLocation ? false,
   withSerialPort ? false,
   withTools ? false,
-  pkgsBuildTarget,
   dbusSupport ? !stdenv.hostPlatform.isDarwin,
 }:
 
@@ -120,42 +118,22 @@ buildPythonPackage rec {
 
   nativeBuildInputs = [
     pkg-config
-  ]
-  ++ lib.optionals (stdenv.buildPlatform == stdenv.hostPlatform) [ libsForQt5.qmake ]
-  ++ [
+    libsForQt5.qmake
     setuptools
-    lndir
     sip
-  ]
-  ++ (
-    with pkgsBuildTarget.targetPackages.libsForQt5;
-    [ ]
-    ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [ qmake ]
-    ++ [
-      qtbase
-      qtsvg
-      qtdeclarative
-      qtwebchannel
-    ]
-    ++ lib.optional withConnectivity qtconnectivity
-    ++ lib.optional withMultimedia qtmultimedia
-    ++ lib.optional withWebKit qtwebkit
-    ++ lib.optional withWebSockets qtwebsockets
-    ++ lib.optional withLocation qtlocation
-    ++ lib.optional withSerialPort qtserialport
-    ++ lib.optional withTools qttools
-  );
+  ];
 
   buildInputs =
     with libsForQt5;
-    [ dbus ]
-    ++ lib.optionals (stdenv.buildPlatform == stdenv.hostPlatform) [ qtbase ]
-    ++ [
+    [
+      dbus
+      qtbase
       qtsvg
       qtdeclarative
       pyqt-builder
     ]
     ++ lib.optional withConnectivity qtconnectivity
+    ++ lib.optional withMultimedia qtmultimedia
     ++ lib.optional withWebKit qtwebkit
     ++ lib.optional withWebSockets qtwebsockets
     ++ lib.optional withLocation qtlocation
diff --git a/pkgs/development/python-modules/pyqtwebengine/default.nix b/pkgs/development/python-modules/pyqtwebengine/default.nix
index 295f8d3ad9916..c3fd199990a25 100644
--- a/pkgs/development/python-modules/pyqtwebengine/default.nix
+++ b/pkgs/development/python-modules/pyqtwebengine/default.nix
@@ -18,95 +18,76 @@
 let
   inherit (darwin) autoSignDarwinBinariesHook;
 in
-buildPythonPackage (
-  rec {
-    pname = "pyqtwebengine";
-    version = "5.15.7";
-    pyproject = true;
+buildPythonPackage rec {
+  pname = "pyqtwebengine";
+  version = "5.15.7";
+  pyproject = true;
 
-    disabled = isPy27;
+  disabled = isPy27;
 
-    src = fetchPypi {
-      pname = "PyQtWebEngine";
-      inherit version;
-      hash = "sha256-8SGsbkovlqwolhm8/Df2Tmg2LySjRlU/XWxC76Qiik0=";
-    };
+  src = fetchPypi {
+    pname = "PyQtWebEngine";
+    inherit version;
+    hash = "sha256-8SGsbkovlqwolhm8/Df2Tmg2LySjRlU/XWxC76Qiik0=";
+  };
 
-    postPatch = ''
-      substituteInPlace pyproject.toml \
-        --replace "[tool.sip.project]" "[tool.sip.project]''\nsip-include-dirs = [\"${pyqt5}/${python.sitePackages}/PyQt5/bindings\"]"
-    '';
+  postPatch = ''
+    substituteInPlace pyproject.toml \
+      --replace "[tool.sip.project]" "[tool.sip.project]''\nsip-include-dirs = [\"${pyqt5}/${python.sitePackages}/PyQt5/bindings\"]"
+  '';
 
-    outputs = [
-      "out"
-      "dev"
-    ];
+  outputs = [
+    "out"
+    "dev"
+  ];
 
-    nativeBuildInputs = [
-      pkg-config
-      libsForQt5.qmake
-      libsForQt5.wrapQtAppsHook
-    ]
-    ++ lib.optionals (stdenv.buildPlatform == stdenv.hostPlatform) [ sip ]
-    ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
-      python.pythonOnBuildForHost.pkgs.sip
-    ]
-    ++ [
-      libsForQt5.qtbase
-      libsForQt5.qtsvg
-      libsForQt5.qtwebengine
-      pyqt-builder
-      setuptools
-    ]
-    ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [ libsForQt5.qtdeclarative ]
-    ++ lib.optionals (stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64) [
-      autoSignDarwinBinariesHook
-    ];
+  nativeBuildInputs = [
+    pkg-config
+    libsForQt5.qmake
+    libsForQt5.wrapQtAppsHook
+    pyqt-builder
+    setuptools
+  ]
+  ++ lib.optionals (stdenv.buildPlatform == stdenv.hostPlatform) [ sip ]
+  ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
+    python.pythonOnBuildForHost.pkgs.sip
+  ]
+  ++ lib.optionals (stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64) [
+    autoSignDarwinBinariesHook
+  ];
 
-    buildInputs = [
-      sip
-      libsForQt5.qtbase
-      libsForQt5.qtsvg
-      libsForQt5.qtwebengine
-    ]
-    ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [
-      libsForQt5.qtwebchannel
-      libsForQt5.qtdeclarative
-    ];
+  buildInputs = [
+    sip
+    libsForQt5.qtbase
+    libsForQt5.qtsvg
+    libsForQt5.qtwebengine
+  ];
 
-    propagatedBuildInputs = [ pyqt5 ];
+  propagatedBuildInputs = [ pyqt5 ];
 
-    dontWrapQtApps = true;
+  dontWrapQtApps = true;
 
-    # Avoid running qmake, which is in nativeBuildInputs
-    dontConfigure = true;
+  # Avoid running qmake, which is in nativeBuildInputs
+  dontConfigure = true;
 
-    # Checked using pythonImportsCheck
-    doCheck = false;
+  # Checked using pythonImportsCheck
+  doCheck = false;
 
-    pythonImportsCheck = [
-      "PyQt5.QtWebEngine"
-      "PyQt5.QtWebEngineWidgets"
-    ];
+  pythonImportsCheck = [
+    "PyQt5.QtWebEngine"
+    "PyQt5.QtWebEngineWidgets"
+  ];
 
-    enableParallelBuilding = true;
+  enableParallelBuilding = true;
 
-    passthru = {
-      inherit (libsForQt5) wrapQtAppsHook;
-    };
+  passthru = {
+    inherit (libsForQt5) wrapQtAppsHook;
+  };
 
-    meta = {
-      description = "Python bindings for Qt5";
-      homepage = "http://www.riverbankcomputing.co.uk";
-      license = lib.licenses.gpl3;
-      hydraPlatforms = lib.lists.intersectLists libsForQt5.qtwebengine.meta.platforms mesa.meta.platforms;
-    };
-  }
-  // lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform) {
-    # TODO: figure out why the env hooks aren't adding these inclusions automatically
-    env.NIX_CFLAGS_COMPILE = lib.concatStringsSep " " [
-      "-I${lib.getDev libsForQt5.qtbase}/include/QtPrintSupport/"
-      "-I${lib.getDev libsForQt5.qtwebchannel}/include/QtWebChannel/"
-    ];
-  }
-)
+  meta = {
+    description = "Python bindings for Qt5";
+    homepage = "http://www.riverbankcomputing.co.uk";
+    license = lib.licenses.gpl3;
+    hydraPlatforms = lib.lists.intersectLists libsForQt5.qtwebengine.meta.platforms mesa.meta.platforms;
+  };
+}
diff --git a/pkgs/development/tools/misc/distcc/masq.nix b/pkgs/development/tools/misc/distcc/masq.nix
index 78cbccb2c565f..7cb97ad5ab7d0 100644
--- a/pkgs/development/tools/misc/distcc/masq.nix
+++ b/pkgs/development/tools/misc/distcc/masq.nix
@@ -42,6 +42,14 @@ stdenv.mkDerivation {
         ln -sf $bbin/*-as $out/bin/as
       done
     fi
+
+    if [ -f $bbin/ar ]; then
+      ln -s $bbin/ar $out/bin
+    else
+      for a in $bbin/*-ar; do
+        ln -sf $bbin/*-ar $out/bin/ar
+      done
+    fi
   '';
 
   meta = {
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 9cd2ced0ed467..8e883b871f033 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -7484,35 +7484,7 @@ with pkgs;
     python3 = null;
   };
 
-  qt5 = recurseIntoAttrs (
-    makeOverridable (import ../development/libraries/qt-5/5.15) {
-      inherit (__splicedPackages)
-        makeScopeWithSplicing'
-        generateSplicesForMkScope
-        lib
-        stdenv
-        gcc14Stdenv
-        fetchurl
-        fetchpatch
-        fetchgit
-        fetchFromGitHub
-        makeSetupHook
-        makeWrapper
-        bison
-        cups
-        dconf
-        harfbuzz
-        libGL
-        perl
-        gtk3
-        python3
-        llvmPackages_19
-        darwin
-        ;
-      inherit (__splicedPackages.gst_all_1) gstreamer gst-plugins-base;
-      inherit config;
-    }
-  );
+  qt5 = recurseIntoAttrs (__splicedPackages.callPackage ../development/libraries/qt-5/5.15 { });
 
   libsForQt5 = recurseIntoAttrs (
     import ./qt5-packages.nix {