added in Nirbheek's patches from aws#1839

CMakeLists.txt

@@ -290,6 +290,22 @@ if (LEGACY_BUILD)
         set(ARCHIVE_DIRECTORY "${LIBRARY_DIRECTORY}")
     endif ()
 
+    # We need to point this to the directory containing import libraries or static
+    # libraries on Windows, and to the directory containing the so / dylib
+    # libraries on other platforms.
+    if(WIN32)
+        set(PKG_CONFIG_LIB_DIRECTORY "${ARCHIVE_DIRECTORY}")
+    else()
+        set(PKG_CONFIG_LIB_DIRECTORY "${LIBRARY_DIRECTORY}")
+    endif()
+
+    # MSVC consumers of the shared library need to define this macro when linking
+    # to aws-cpp-sdk-* libs, or they will get undefined reference errors. Also
+    # doesn't hurt to define this with MinGW, so add it unconditionally on Windows.
+    if(WIN32 AND BUILD_SHARED_LIBS)
+        set(PKG_CONFIG_EXPORT_CFLAGS "-DUSE_IMPORT_EXPORT")
+    endif()
+
     if (ENABLE_ADDRESS_SANITIZER)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address -g -fno-omit-frame-pointer")
         if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 7.1)

toolchains/pkg-config.pc.in

@@ -4,7 +4,7 @@ libdir=@CMAKE_INSTALL_PREFIX@/@LIBRARY_DIRECTORY@
 Name: @PROJECT_NAME@
 Description: @PROJECT_DESCRIPTION@
 Version: @PROJECT_VERSION@
-Cflags: -I${includedir} @PKG_CONFIG_CFLAGS@
+Cflags: -I${includedir} @PKG_CONFIG_CFLAGS@ @PKG_CONFIG_EXPORT_CFLAGS@
 Libs: -L${libdir} -l@PROJECT_NAME@ 
 Libs.private: @ALL_DEP_LIBS_LINK_FLAGS@
 Requires: @PROJECT_LIBS_STRING@