gjay: disable format hardening

pkgs/applications/audio/gjay/default.nix

···
 
   buildInputs = [ mpd_clientlib dbus_glib audacious gtk gsl libaudclient ];
 
+  hardeningDisable = [ "format" ];
+
   meta = with stdenv.lib; {
     description = "Generates playlists such that each song sounds good following the previous song";
     homepage = http://gjay.sourceforge.net/;