fortune: remove gcc from closure

Fixup is only run on $out/bin not $out/games. Luckily fortune is
relocatable so just moving it to $out/bin works & reduces closure size.

pkgs/tools/misc/fortune/default.nix

@@ -19,7 +19,8 @@ stdenv.mkDerivation {
   '';
 
   postInstall = ''
-    ln -s $out/games/fortune $out/bin/fortune
+    mv $out/games/fortune $out/bin/fortune
+    rmdir $out/games
   '';
 
   meta = {