Ports/doom: Use upstream doomgeneric SDL port

Doing this means we no longer need to maintain our own Doom fork and
we get  the newest features of the upstream repository, such as sound
effects and music.

Ports/doom/patches/0002-Use-SDL-software-renderer.patch

@@ -0,0 +1,22 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Tim Ledbetter <timledbetter@gmail.com>
+Date: Sat, 5 Aug 2023 09:55:31 +0100
+Subject: [PATCH] Use SDL software renderer
+
+---
+ doomgeneric/doomgeneric_sdl.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/doomgeneric/doomgeneric_sdl.c b/doomgeneric/doomgeneric_sdl.c
+index fd4236a83be0f99fce777c494f3b92faa341567f..725339d818fd6c969f431c181eb5c69fd7c765c6 100644
+--- a/doomgeneric/doomgeneric_sdl.c
++++ b/doomgeneric/doomgeneric_sdl.c
+@@ -141,7 +141,7 @@ void DG_Init(){
+                             );
+ 
+   // Setup renderer
+-  renderer =  SDL_CreateRenderer( window, -1, SDL_RENDERER_ACCELERATED);
++  renderer =  SDL_CreateRenderer( window, -1, SDL_RENDERER_SOFTWARE);
+   // Clear winow
+   SDL_RenderClear( renderer );
+   // Render the rect to the screen