Bug 676150 GDK: Fix build on Windows

-Don't include unistd.h and stdint.h unconditionally as not all Windows
 compilers have them around.
-Only include cogl/cogl-xlib.h when it is really supported by Cogl and GDK.
-sys/ioctl.h is not available on Windows (MinGW/MSVC).
-Correct the call to cogl_renderer_set_winsys_id:
 (backend_cogl->cogl_renderer, COGL_WINSYS_ID_WGL) ->
 (renderer, COGL_WINSYS_ID_WGL)

clutter/gdk/clutter-device-manager-gdk.c

@@ -24,7 +24,9 @@
 
 #include "config.h"
 
+#ifdef HAVE_STDINT_H
 #include <stdint.h>
+#endif
 
 #include "clutter-device-manager-gdk.h"