caca: allow to define the CACA_STATIC macro to deactivate dllimport

specifiers; this is required for proper static link.

caca/caca.h

@@ -31,7 +31,7 @@
 #if defined _DOXYGEN_SKIP_ME
 #elif defined _WIN32 && defined __LIBCACA__ && defined DLL_EXPORT
 #   define __extern extern __declspec(dllexport)
-#elif defined _WIN32 && !defined __LIBCACA__
+#elif defined _WIN32 && !defined __LIBCACA__ && !defined CACA_STATIC
 #   define __extern extern __declspec(dllimport)
 #else
 #   define __extern extern