Enable building git2.rc resource script with GCC

src/CMakeLists.txt

@@ -278,10 +278,12 @@ list(SORT SRC_H)
 
 # On Windows use specific platform sources
 if(WIN32 AND NOT CYGWIN)
-	if(MSVC)
-		SET(WIN_RC "win32/git2.rc")
+	if(NOT MSVC)
+		ADD_DEFINITIONS(-DGCC_WINDRES)
 	endif()
 
+	SET(WIN_RC "win32/git2.rc")
+
 	file(GLOB SRC_OS win32/*.c win32/*.h)
 	list(SORT SRC_OS)
 elseif(AMIGA)

src/win32/git2.rc

@@ -9,7 +9,18 @@
 # define LIBGIT2_COMMENTS "For more information visit http://libgit2.github.com/"
 #endif
 
+#ifdef GCC_WINDRES
+# define STRINGIZE(x) #x
+# define STRINGIZE_(x) STRINGIZE(x)
+#else
+# define STRINGIZE_(x) x
+#endif
+
+#ifdef GCC_WINDRES
+VS_VERSION_INFO		VERSIONINFO
+#else
 VS_VERSION_INFO		VERSIONINFO	MOVEABLE IMPURE LOADONCALL DISCARDABLE
+#endif
   FILEVERSION		LIBGIT2_VER_MAJOR,LIBGIT2_VER_MINOR,LIBGIT2_VER_REVISION,LIBGIT2_VER_PATCH
   PRODUCTVERSION	LIBGIT2_VER_MAJOR,LIBGIT2_VER_MINOR,LIBGIT2_VER_REVISION,LIBGIT2_VER_PATCH
   FILEFLAGSMASK		VS_FFI_FILEFLAGSMASK
@@ -29,9 +40,9 @@ BEGIN
     BEGIN
       VALUE "FileDescription",	"libgit2 - the Git linkable library\0"
       VALUE "FileVersion",	LIBGIT2_VERSION "\0"
-      VALUE "InternalName",	LIBGIT2_FILENAME ".dll\0"
+      VALUE "InternalName",	STRINGIZE_(LIBGIT2_FILENAME) ".dll\0"
       VALUE "LegalCopyright",	"Copyright (C) the libgit2 contributors. All rights reserved.\0"
-      VALUE "OriginalFilename",	LIBGIT2_FILENAME ".dll\0"
+      VALUE "OriginalFilename",	STRINGIZE_(LIBGIT2_FILENAME) ".dll\0"
       VALUE "ProductName",	"libgit2\0"
       VALUE "ProductVersion",	LIBGIT2_VERSION "\0"
       VALUE "Comments",		LIBGIT2_COMMENTS "\0"