diff --git a/src/main/macosx/SDLMain.h b/src/main/macosx/SDLMain.h
index 4683df57a..c56d90cbe 100644
--- a/src/main/macosx/SDLMain.h
+++ b/src/main/macosx/SDLMain.h
@@ -5,7 +5,12 @@
     Feel free to customize this file to suit your needs
 */
 
+#ifndef _SDLMain_h_
+#define _SDLMain_h_
+
 #import <Cocoa/Cocoa.h>
 
 @interface SDLMain : NSObject
 @end
+
+#endif /* _SDLMain_h_ */