anchor.diff:      core = "smsplus";
       src = getCoreSrc "smsplus-gx";
       description = "SMS Plus GX libretro port";
  -    license = gpl2Plus;
  +    license = lib.licenses.gpl2Plus;
     };
   
     snes9x = mkLibRetroCore {
  
positive.code:   play = mkLibRetroCore {
      core = "play";
      description = "Port of Play! to libretro";
      license = bsd2;
      extraBuildInputs = [ boost ];
      extraNativeBuildInputs = [ cmake openssl curl icu libGL libGLU xorg.libX11 ];
      makefile = "Makefile";
  
negative.code:   gpsp = mkLibRetroCore {
      core = "gpsp";
      description = "Port of gpSP to libretro";
      license = lib.licenses.gpl2Only;
      makefile = "Makefile";
    };
  
  