angband: add SDL2 frontend

This makes it possible to compile Angband against SDL2 (and its other
libraries) to have a graphical frontend available, with tiles and
sound.  The default remains ASCII-only Angband; enable SDL2 by using
an override.

Co-authored-by: Sandro <sandro.jaeckel@gmail.com>

pkgs/games/angband/default.nix

@@ -1,4 +1,6 @@
-{ lib, stdenv, fetchFromGitHub, autoreconfHook, ncurses5 }:
+{ lib, stdenv, fetchFromGitHub, autoreconfHook, ncurses5
+, enableSdl2 ? false, SDL2, SDL2_image, SDL2_sound, SDL2_mixer, SDL2_ttf
+}:
 
 stdenv.mkDerivation rec {
   pname = "angband";
@@ -11,8 +13,19 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-Fp3BGCZYYdQCKXOLYsT4zzlibNRlbELZi26ofrbGGPQ=";
   };
 
+
   nativeBuildInputs = [ autoreconfHook ];
-  buildInputs = [ ncurses5 ];
+  buildInputs = [ ncurses5 ]
+  ++ lib.optionals enableSdl2 [
+    SDL2
+    SDL2_image
+    SDL2_sound
+    SDL2_mixer
+    SDL2_ttf
+  ];
+
+  configureFlags = lib.optional enableSdl2 "--enable-sdl2";
+
   installFlags = [ "bindir=$(out)/bin" ];
 
   meta = with lib; {