lbreakout2: fix build on Darwin

pkgs/games/lbreakout2/default.nix

···
-{ stdenv, fetchurl, SDL, SDL_mixer, zlib, libpng }:
+{ stdenv, fetchurl, SDL, SDL_mixer, zlib, libpng, libintlOrEmpty }:
 
 stdenv.mkDerivation rec {
   name = "lbreakout2-${version}";
   version = "2.6.5";
-  buildInputs = [ SDL SDL_mixer zlib libpng ];
+  buildInputs = [ SDL SDL_mixer zlib libpng ] ++ libintlOrEmpty;
 
   src = fetchurl {
     url = "mirror://sourceforge/lgames/${name}.tar.gz";
     sha256 = "0vwdlyvh7c4y80q5vp7fyfpzbqk9lq3w8pvavi139njkalbxc14i";
   };
 
+  NIX_LDFLAGS = stdenv.lib.optionalString stdenv.isDarwin "-lintl";
+
   meta = with stdenv.lib; {
     description = "Breakout clone from the LGames series";
     homepage = http://lgames.sourceforge.net/LBreakout2/;
     license = licenses.gpl2;
     maintainers = [ maintainers.ciil ];
-    platforms = platforms.linux;
+    platforms = platforms.unix;
   };
 }
-