chocolate-doom: only build on linux

darwin build times out on sdl-config

pkgs/games/chocolate-doom/default.nix

@@ -19,6 +19,7 @@ stdenv.mkDerivation rec {
     description = "A Doom source port that accurately reproduces the experience of Doom as it was played in the 1990s";
     license = stdenv.lib.licenses.gpl2Plus;
     platforms = stdenv.lib.platforms.unix;
+    hydraPlatforms = stdenv.lib.platforms.linux; # darwin times out
     maintainers = with stdenv.lib.maintainers; [ MP2E ];
   };
 }