Fixed case-correctness of an #include (see issue #790)

platform/macosx/OSX.mm

@@ -18,7 +18,7 @@
  * 3. This notice may not be removed or altered from any source distribution.
  **/
 
-#import "osx.h"
+#import "OSX.h"
 #import <Foundation/Foundation.h>
 
 #include <SDL2/SDL.h>

src/love.cpp

@@ -35,7 +35,7 @@ extern "C" {
 #endif // LOVE_WINDOWS
 
 #ifdef LOVE_MACOSX
-#include "osx.h"
+#include "OSX.h"
 #endif // LOVE_MACOSX
 
 #ifdef LOVE_LEGENDARY_UTF8_ARGV_HACK