Fix Cg linking on OSX

Author: revmischa

src/libprojectM/CMakeLists.txt

@@ -80,7 +80,12 @@ endif (USE_DEVIL)
 
 if (USE_CG)
 	ADD_DEFINITIONS(-DUSE_CG)
-	SET (CG_LINK_TARGETS Cg CgGL)
+
+	if (APPLE)
+		FIND_LIBRARY(CG_LINK_TARGETS Cg)
+	else (APPLE)
+		SET (CG_LINK_TARGETS Cg CgGL)
+	endif (APPLE)
 else (USE_CG)
 	SET (CG_LINK_TARGETS)
 endif(USE_CG)