yquake2: move icon to spec-compliant location and fix build with GCC 15 (#492744)

pkgs/games/quake2/yquake2/default.nix

@@ -74,7 +74,7 @@ let
       ln -s $out/lib/yquake2/quake2 $out/bin/yquake2
       ln -s $out/lib/yquake2/q2ded $out/bin/yq2ded
       cp $src/stuff/yq2.cfg $out/share/games/quake2/baseq2
-      install -Dm644 stuff/icon/Quake2.png $out/share/pixmaps/yamagi-quake2.png;
+      install -Dm644 stuff/icon/Quake2.png $out/share/icons/hicolor/512x512/apps/yamagi-quake2.png;
       runHook postInstall
     '';
 

pkgs/games/quake2/yquake2/games.nix

@@ -48,6 +48,12 @@ let
         rev = "${lib.toUpper id}_${builtins.replaceStrings [ "." ] [ "_" ] version}";
       };
 
+      env =
+        # Uses `false` and `true` as enum constants, which are keywords in C23 (GCC 15 default)
+        lib.optionalAttrs stdenv.cc.isGNU {
+          NIX_CFLAGS_COMPILE = "-std=gnu17";
+        };
+
       installPhase = ''
         runHook preInstall
         mkdir -p $out/lib/yquake2/${id}

pkgs/games/quake2/yquake2/wrapper.nix

@@ -43,7 +43,7 @@ stdenv.mkDerivation {
       --add-flags "+set game ${game.id}"
   '') games
   + ''
-    install -Dm644 ${yquake2}/share/pixmaps/yamagi-quake2.png $out/share/pixmaps/yamagi-quake2.png;
+    install -Dm644 ${yquake2}/share/icons/hicolor/512x512/apps/yamagi-quake2.png $out/share/icons/hicolor/512x512/apps/yamagi-quake2.png;
     runHook postInstall
   '';