Properly initialize NSApplication on Mac OS X

This was previously fixed, but broken again  when we moved main() out
of Core.cpp.

Fixes: bug #514

src/core/Core.cpp

@@ -146,15 +146,6 @@ ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
 
 #include "window/RenderWindow.h"
 
-// Under OS X we want SDLmain to replace the entry point with its own.
-// TODO: I don't think this is wanted and we'll need to add the NSApplication setup
-// on the Arx Libertatis side instead of SDLmain's.
-#if defined(__APPLE__) && defined(__MACH__)
-	#include <SDL_main.h>
-#else
-	#undef main /* in case SDL.h was already included */
-#endif
-
 class TextManager;
 
 using std::min;

src/core/Startup.cpp

@@ -37,6 +37,17 @@
 
 #include <boost/foreach.hpp>
 
+/*
+ * Under OS X we want SDLmain to replace the entry point with its own.
+ * This is needed to initialize NSApplication - otherwise we will later
+ * crash when trying to use SDL windowing functions.
+ */
+#if defined(__APPLE__) && defined(__MACH__)
+	#include <SDL_main.h>
+#else
+	#undef main /* in case SDL.h was already included */
+#endif
+
 #include "core/Config.h"
 #include "core/Core.h"
 #include "core/Version.h"