Fixed compilation issues with GCC 4.0.1 PowerPC

src/cocoa/i_backend_cocoa.mm

@@ -41,6 +41,7 @@
 
 #include <AppKit/AppKit.h>
 #include <Carbon/Carbon.h>
+#include <OpenGL/OpenGL.h>
 #include <OpenGL/gl.h>
 
 #include <SDL.h>

src/cocoa/i_timer.cpp

@@ -2,6 +2,7 @@
 #include <assert.h>
 #include <sys/time.h>
 #include <pthread.h>
+#include <libkern/OSAtomic.h>
 
 #include <SDL.h>
 
@@ -92,7 +93,12 @@ void* TimerThreadFunc(void*)
 
 		if (!g_isTicFrozen)
 		{
-			__sync_add_and_fetch(&s_tics, 1);
+			// The following GCC/Clang intrinsic can be used instead of OS X specific function:
+			// __sync_add_and_fetch(&s_tics, 1);
+			// Although it's not supported on all platform/compiler combination,
+			// e.g. GCC 4.0.1 with PowerPC target architecture
+
+			OSAtomicIncrement32(&s_tics);
 		}
 
 		s_timerStart = SDL_GetTicks();