Added code to enable multi-threaded OpenGL on Mac OS X, pending Ryan's PBO/VBO

changes.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%402608

src/video/SDL_renderer_gl.c

@@ -30,6 +30,10 @@
 #include "SDL_rect_c.h"
 #include "SDL_yuv_sw_c.h"
 
+#ifdef __MACOSX__
+#include <OpenGL/OpenGL.h>
+#endif
+
 /* OpenGL renderer implementation */
 
 /* Details on optimizing the texture path on Mac OS X:
@@ -292,6 +296,13 @@ GL_CreateRenderer(SDL_Window * window, Uint32 flags)
         return NULL;
     }
 
+#ifdef __MACOSX__
+    /* Enable multi-threaded rendering */
+    /* Disabled until Ryan finishes his VBO/PBO code...
+    CGLEnable(CGLGetCurrentContext(), kCGLCEMPEngine);
+    */
+#endif
+
     if (flags & SDL_RENDERER_PRESENTVSYNC) {
         SDL_GL_SetSwapInterval(1);
     } else {