Move packages into overlays as God intended

overlays/packages/xash3d/change-zip-date.patch

@@ -0,0 +1,17 @@
+diff --git a/scripts/waifulib/zip.py b/scripts/waifulib/zip.py
+index 6e903ba7..d47f1754 100644
+--- a/scripts/waifulib/zip.py
++++ b/scripts/waifulib/zip.py
+@@ -25,7 +25,11 @@ class ziparchive(Task.Task):
+ 				arcfile = src.path_from(self.relative_to)
+ 
+ 				Logs.debug('%s: %s <- %s as %s', self.__class__.__name__, outfile, infile, arcfile)
+-				zf.write(infile, arcfile)
++
++				arcfile = zipfile.ZipInfo(filename=arcfile, date_time=(1980, 1, 1, 0, 0, 0))
++
++				with open(infile, 'rb') as f:
++					zf.writestr(arcfile, f.read())
+ 
+ @TaskGen.feature('zip')
+ def create_zip_archive(self):

overlays/packages/xash3d/default.nix

@@ -0,0 +1,68 @@
+{ lib
+, pkgs
+, stdenv
+, fetchFromGitHub
+, dedicated ? false # dedicated server
+, gamedir ? "valve"
+, enableBsp2 ? false # bsp2 support (for quake)
+, enableGles1 ? false # gles1 renderer (nanogl)
+, enableGles2 ? false # gles2 renderer (glwes)
+, enableGl4es ? false # gles2 renderer (gl4es)
+, enableGl ? true # opengl renderer
+, enableSoft ? true # soft renderer
+, enableUtils ? false # mdldec
+}:
+
+stdenv.mkDerivation {
+  pname = "xash3d-fwgs";
+  version = "2023-03-01";
+
+  nativeBuildInputs = with pkgs; [python3 pkg-config makeWrapper];
+  buildInputs = with pkgs; [SDL2 libopus freetype fontconfig];
+
+  src = fetchFromGitHub {
+    owner = "FWGS";
+    repo = "xash3d-fwgs";
+    rev = "7e9d46689ca76d6bf1669ada6344fc724dd683cf";
+    sha256 = "sha256-rvONYm1Gz9PpK8KY6RIIJ82FtxGcWe/4YoT2eV4sCOc=";
+    fetchSubmodules = true;
+  };
+  patches = [ ./change-zip-date.patch ];
+
+  configurePhase = let
+    optionals = lib.optionals;
+    optional = (cond: val: optionals cond [val]);
+    flags = ["-8" "-P" "--prefix=/"]
+      ++ (optional dedicated "-d")
+      ++ (optionals (gamedir != "valve") ["--gamedir" gamedir])
+      ++ (optional enableBsp2 "--enable-bsp2")
+      ++ (optional enableGles1 "--enable-gles1")
+      ++ (optional enableGles2 "--enable-gles2")
+      ++ (optional enableGl4es "--enable-gl4es")
+      ++ (optional (!enableGl) "--disable-gl")
+      ++ (optional (!enableSoft) "--disable-soft")
+      ++ (optional enableUtils "--enable-utils")
+    ;
+  in ''
+    python3 ./waf configure -T release ${lib.strings.escapeShellArgs flags}
+  '';
+
+  buildPhase = ''
+    python3 ./waf build
+  '';
+
+  installPhase = ''
+    python3 ./waf install "--destdir=$out"
+    mkdir $out/bin
+    makeWrapper $out/lib/xash3d/xash3d $out/bin/xash3d --set XASH3D_EXTRAS_PAK1 $out/share/xash3d/valve/extras.pk3
+  '';
+
+  meta = with lib; {
+    description = "Xash3D FWGS engine";
+    homepage = "https://github.com/FWGS/xash3d-fwgs";
+    # this is a mess because of vendoring...
+    # maybe the correct thing to do use to simply use `[ unfree gpl3Plus ]` instead
+    license = with licenses; [ unfree gpl2Plus gpl3Plus lgpl3Plus mit bsd3 ];
+    # maintainers = with maintainers; [ chayleaf ];
+  };
+}