Only include libmumblelink.h if USE_MUMBLE is defined, reported by Ensiform.

code/client/cl_cgame.c

@@ -25,7 +25,9 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 
 #include "../botlib/botlib.h"
 
+#ifdef USE_MUMBLE
 #include "libmumblelink.h"
+#endif
 
 extern	botlib_export_t	*botlib_export;