Use SDL 2 instead of SDL 1.2

code/renderer/tr_local.h

@@ -1077,6 +1077,7 @@ extern cvar_t	*r_mode;				// video mode
 extern cvar_t	*r_fullscreen;
 extern cvar_t	*r_noborder;
 extern cvar_t	*r_gamma;
+extern cvar_t	*r_displayRefresh;		// optional display refresh option
 extern cvar_t	*r_ignorehwgamma;		// overrides hardware gamma capabilities
 
 extern cvar_t	*r_allowExtensions;				// global enable/disable of OpenGL extensions