Merge pull request #3252 from Tachi107/build-cmake-pkg-config-always

build(cmake): improve pkg-config generation

build/cmake/CMakeModules/JoinPaths.cmake

@@ -0,0 +1,23 @@
+# This module provides function for joining paths
+# known from most languages
+#
+# SPDX-License-Identifier: (MIT OR CC0-1.0)
+# Copyright 2020 Jan Tojnar
+# https://github.com/jtojnar/cmake-snips
+#
+# Modelled after Python’s os.path.join
+# https://docs.python.org/3.7/library/os.path.html#os.path.join
+# Windows not supported
+function(join_paths joined_path first_path_segment)
+    set(temp_path "${first_path_segment}")
+    foreach(current_segment IN LISTS ARGN)
+        if(NOT ("${current_segment}" STREQUAL ""))
+            if(IS_ABSOLUTE "${current_segment}")
+                set(temp_path "${current_segment}")
+            else()
+                set(temp_path "${temp_path}/${current_segment}")
+            endif()
+        endif()
+    endforeach()
+    set(${joined_path} "${temp_path}" PARENT_SCOPE)
+endfunction()

build/cmake/lib/CMakeLists.txt

@@ -135,30 +135,17 @@ if (ZSTD_BUILD_STATIC)
             OUTPUT_NAME ${STATIC_LIBRARY_BASE_NAME})
 endif ()
 
-if (UNIX OR MINGW)
-    # pkg-config
-    set(PREFIX "${CMAKE_INSTALL_PREFIX}")
-    set(EXEC_PREFIX "\${prefix}")
-    set(LIBDIR "${CMAKE_INSTALL_FULL_LIBDIR}")
-    set(INCLUDEDIR "${CMAKE_INSTALL_FULL_INCLUDEDIR}")
-    set(VERSION "${zstd_VERSION}")
-
-    string(LENGTH "${PREFIX}" PREFIX_LENGTH)
-    string(SUBSTRING "${LIBDIR}" 0 ${PREFIX_LENGTH} LIBDIR_PREFIX)
-    string(SUBSTRING "${LIBDIR}" ${PREFIX_LENGTH} -1 LIBDIR_SUFFIX)
-    string(SUBSTRING "${INCLUDEDIR}" 0 ${PREFIX_LENGTH} INCLUDEDIR_PREFIX)
-    string(SUBSTRING "${INCLUDEDIR}" ${PREFIX_LENGTH} -1 INCLUDEDIR_SUFFIX)
-
-    if ("${INCLUDEDIR_PREFIX}" STREQUAL "${PREFIX}")
-        set(INCLUDEDIR "\${prefix}${INCLUDEDIR_SUFFIX}")
-    endif()
-    if ("${LIBDIR_PREFIX}" STREQUAL "${PREFIX}")
-        set(LIBDIR "\${exec_prefix}${LIBDIR_SUFFIX}")
-    endif()
-
-    configure_file("${LIBRARY_DIR}/libzstd.pc.in" "${CMAKE_CURRENT_BINARY_DIR}/libzstd.pc" @ONLY)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/libzstd.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
-endif ()
+# pkg-config
+include(JoinPaths) # can be replaced by cmake_path(APPEND) in CMake 3.20
+set(PREFIX "${CMAKE_INSTALL_PREFIX}")
+set(EXEC_PREFIX "\${prefix}")
+join_paths(LIBDIR "\${exec_prefix}" "${CMAKE_INSTALL_LIBDIR}")
+join_paths(INCLUDEDIR "\${prefix}" "${CMAKE_INSTALL_INCLUDEDIR}")
+set(LIBS_PRIVATE "${THREADS_LIBS}")
+set(VERSION "${zstd_VERSION}")
+
+configure_file("${LIBRARY_DIR}/libzstd.pc.in" "${CMAKE_CURRENT_BINARY_DIR}/libzstd.pc" @ONLY)
+install(FILES "${CMAKE_CURRENT_BINARY_DIR}/libzstd.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
 # install target
 install(FILES