[Backport release-25.05] qt6.qtwebengine: fix build

pkgs/development/libraries/qt-6/modules/qtwebengine/default.nix

@@ -7,6 +7,7 @@
   buildPackages,
   bison,
   coreutils,
+  fetchpatch2,
   flex,
   git,
   gperf,
@@ -100,20 +101,30 @@ qtModule {
   # which cannot be set at the same time as -Wformat-security
   hardeningDisable = [ "format" ];
 
-  patches = [
-    # Don't assume /usr/share/X11, and also respect the XKB_CONFIG_ROOT
-    # environment variable, since NixOS relies on it working.
-    # See https://github.com/NixOS/nixpkgs/issues/226484 for more context.
-    ./xkb-includes.patch
+  patches =
+    [
+      # Don't assume /usr/share/X11, and also respect the XKB_CONFIG_ROOT
+      # environment variable, since NixOS relies on it working.
+      # See https://github.com/NixOS/nixpkgs/issues/226484 for more context.
+      ./xkb-includes.patch
 
-    ./link-pulseaudio.patch
+      ./link-pulseaudio.patch
 
-    # Override locales install path so they go to QtWebEngine's $out
-    ./locales-path.patch
+      # Override locales install path so they go to QtWebEngine's $out
+      ./locales-path.patch
 
-    # Reproducibility QTBUG-136068
-    ./gn-object-sorted.patch
-  ];
+      # Reproducibility QTBUG-136068
+      ./gn-object-sorted.patch
+    ]
+    ++ lib.optionals stdenv.cc.isClang [
+      # https://chromium-review.googlesource.com/c/chromium/src/+/6445471
+      (fetchpatch2 {
+        url = "https://github.com/chromium/chromium/commit/f8f21fb4aa01f75acbb12abf5ea8c263c6817141.patch?full_index=1";
+        stripLen = 1;
+        extraPrefix = "src/3rdparty/chromium/";
+        hash = "sha256-wcby9uD8xb4re9+s+rdl1hcpxDcHxuI68vUNAC7Baas=";
+      })
+    ];
 
   postPatch =
     ''