Fix infinite vid_restart loop from SDL resize events on macOS

On macOS, the SDL2 Cocoa backend fires SDL_WINDOWEVENT_RESIZED during
fullscreen window creation as the window goes through a size negotiation
with the window server. Since vid_restart destroys and recreates the SDL
window, each restart triggers a resize event with the same dimensions,
which sets vidRestartTime, which fires another vid_restart one second
later, creating an infinite loop.

This does not occur on Linux or Windows where the X11/Win32 backends do
not emit resize events during fullscreen window creation.

Skip the vidRestartTime when the reported dimensions match what
r_customwidth and r_customheight already hold.

Author: jackharrhy

code/sdl/sdl_input.c

@@ -1185,17 +1185,26 @@ static void IN_ProcessEvents( void )
 				{
 					case SDL_WINDOWEVENT_RESIZED:
 						{
-							char width[32], height[32];
-							Com_sprintf( width, sizeof( width ), "%d", e.window.data1 );
-							Com_sprintf( height, sizeof( height ), "%d", e.window.data2 );
-							Cvar_Set( "r_customwidth", width );
-							Cvar_Set( "r_customheight", height );
-							Cvar_Set( "r_mode", "-1" );
-
-							// Wait until user stops dragging for 1 second, so
-							// we aren't constantly recreating the GL context while
-							// he tries to drag...
-							vidRestartTime = Sys_Milliseconds( ) + 1000;
+							int newWidth = e.window.data1;
+							int newHeight = e.window.data2;
+
+							// Ignore spurious resize events fired when the window is
+							// recreated at the same size (e.g. after vid_restart on macOS).
+							if( newWidth != Cvar_VariableIntegerValue( "r_customwidth" ) ||
+							    newHeight != Cvar_VariableIntegerValue( "r_customheight" ) )
+							{
+								char width[32], height[32];
+								Com_sprintf( width, sizeof( width ), "%d", newWidth );
+								Com_sprintf( height, sizeof( height ), "%d", newHeight );
+								Cvar_Set( "r_customwidth", width );
+								Cvar_Set( "r_customheight", height );
+								Cvar_Set( "r_mode", "-1" );
+
+								// Wait until user stops dragging for 1 second, so
+								// we aren't constantly recreating the GL context while
+								// he tries to drag...
+								vidRestartTime = Sys_Milliseconds( ) + 1000;
+							}
 						}
 						break;