Include system headers using "#include <file.h>", so GCC will not issue warnings about them.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@331 8ced0084-cf51-0410-be5f-012b33b47a6e

Source/Plugins/Plugin_PadSimple/Src/main.cpp

@@ -43,7 +43,7 @@ DInput dinput;
 
 #else
 
-#include "SDL.h"
+#include <SDL.h>
 SDL_Joystick *joy;
 int numaxes = 0;
 int numbuttons = 0;