Enhance pkg-config generation, state it inside README.md

CMakeModules/FindLibraries.cmake

@@ -5,7 +5,7 @@ find_package(Git REQUIRED)
 find_package(DepotTools REQUIRED)
 find_package(PythonInterp REQUIRED)
 
-list(APPEND LIBWEBRTC_LIBRARIES webrtc Threads::Threads)
+list(APPEND LIBWEBRTC_LIBRARIES webrtc)
 
 if (UNIX AND NOT APPLE)
   find_package(X11 REQUIRED)

CMakeModules/Install.cmake

@@ -34,6 +34,39 @@ install(FILES ${CMAKE_BINARY_DIR}/LibWebRTCConfigVersion.cmake
 #
 # Install pkg-config file
 if (UNIX)
+  set(prefix "${CMAKE_INSTALL_PREFIX}")
+  set(exec_prefix "\${prefix}")
+  set(libdir "${INSTALL_LIB_DIR}")
+  set(includedir "${INSTALL_INCLUDE_DIR}")
+
+  set(LIBWEBRTC_PC_LIBS "-L${INSTALL_LIB_DIR}" "-lwebrtc")
+  foreach(LIB_NAME ${LIBWEBRTC_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
+    if (LIB_NAME MATCHES "[\\/]")
+      get_filename_component(LIB_DIR "${LIB_NAME}" PATH)
+      get_filename_component(LIB_NAME "${LIB_NAME}" NAME_WE)
+      string(REGEX REPLACE "^lib(.*)" "-l\\1" LIB_NAME "${LIB_NAME}")
+
+      if (NOT ${LIB_DIR} IN_LIST LIB_DIRS)
+        list(APPEND LIB_DIRS ${LIB_DIR})
+        list(APPEND LIBWEBRTC_PC_LIBS_PRIVATE "-L${LIB_DIR}")
+      endif (NOT ${LIB_DIR} IN_LIST LIB_DIRS)
+
+    elseif (NOT LIB_NAME MATCHES "^-l")
+      set(LIB_NAME "-l${LIB_NAME}")
+    endif ()
+    list(APPEND LIBWEBRTC_PC_LIBS_PRIVATE "${LIB_NAME}")
+  endforeach(LIB_NAME ${LIBWEBRTC_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
+
+  foreach(DEFINITION ${LIBWEBRTC_DEFINITIONS})
+    list(APPEND LIBWEBRTC_PC_DEFINITIONS "-D${DEFINITION}")
+  endforeach(DEFINITION ${LIBWEBRTC_DEFINITIONS})
+
+  list(REMOVE_ITEM LIBWEBRTC_PC_LIBS_PRIVATE "-lwebrtc")
+  string(REPLACE ";" " " LIBWEBRTC_PC_DEFINITIONS "${LIBWEBRTC_PC_DEFINITIONS}")
+  string(REPLACE ";" " " LIBWEBRTC_PC_LIBS "${LIBWEBRTC_PC_LIBS}")
+  string(REPLACE ";" " " LIBWEBRTC_PC_LIBS_PRIVATE "${LIBWEBRTC_PC_LIBS_PRIVATE}")
+  string(REPLACE ";" " " LIBWEBRTC_PC_CXXFLAGS "${LIBWEBRTC_REQUIRED_CXX_FLAGS}")
+
   configure_file(${CMAKE_MODULE_PATH}/Templates/LibWebRTC.pc.in
                  ${CMAKE_BINARY_DIR}/LibWebRTC.pc @ONLY)
   install(FILES ${CMAKE_BINARY_DIR}/LibWebRTC.pc

CMakeModules/TargetOsAndCpu.cmake

@@ -66,10 +66,15 @@ endif (NOT ${TARGET_CPU} IN_LIST TARGET_CPU_LIST)
 
 if (UNIX)
   if (ARCH_X86)
-    set(LIBWEBRTC_REQUIRED_CXX_FLAGS "-m32")
+    list(APPEND LIBWEBRTC_REQUIRED_CXX_FLAGS "-m32")
   endif (ARCH_X86)
 
-  set(LIBWEBRTC_REQUIRED_CXX_FLAGS "${LIBWEBRTC_REQUIRED_CXX_FLAGS} -std=gnu++0x")
+  list(APPEND LIBWEBRTC_REQUIRED_CXX_FLAGS "-std=gnu++0x")
+
+  if(THREADS_HAVE_PTHREAD_ARG)
+    list(APPEND LIBWEBRTC_REQUIRED_CXX_FLAGS "-pthread")
+  endif()
+
   list(APPEND LIBWEBRTC_DEFINITIONS
        WEBRTC_POSIX _GLIBCXX_USE_CXX11_ABI=0 _CRT_SECURE_NO_WARNINGS)
 elseif (WIN32)

CMakeModules/Templates/LibWebRTC.pc.in

@@ -8,4 +8,4 @@ Description: Google's native WebRTC implementation shipped into a single library
 Version: @LIBWEBRTC_VERSION@
 Libs: @LIBWEBRTC_PC_LIBS@
 Libs.private: @LIBWEBRTC_PC_LIBS_PRIVATE@
-Cflags: -I${includedir}
+Cflags: -I${includedir} @LIBWEBRTC_PC_DEFINITIONS@ @LIBWEBRTC_PC_CXXFLAGS@

README.md

@@ -15,6 +15,12 @@ add_executable(sample ${SOURCE_FILES})
 target_link_libraries(sample ${LIBWEBRTC_LIBRARIES})
 ```
 
+It also produces a `pkg-config` file if you prefer the classic way:
+
+```
+$ g++ `pkg-config --cflags LibWebRTC` main.cpp -o main `pkg-config --libs LibWebRTC`
+```
+
 ## Status
 
 The following table displays the current state of this project, including
@@ -133,6 +139,13 @@ include(${LIBWEBRTC_USE_FILE})
 target_link_libraries(my-app ${LIBWEBRTC_LIBRARIES})
 ```
 
+A pkg-config file is also provided, you can obtain the required compiler and
+linker flags by specifying `LibWebRTC` as the package name.
+
+```
+$ pkg-config --cflags --libs LibWebRTC
+```
+
 ## Configuration
 
 The library will be compiled and usable on the same host's platform and