anchor.diff:  
     NIX_CFLAGS_COMPILE = ''-DLIBGL_PATH="${getLib libGL}/lib"'';
   
  +  # cgl_epoxy_api fails in darwin sandbox and on Hydra (because it's headless?)
  +  preCheck = lib.optionalString stdenv.isDarwin ''
  +    substituteInPlace ../test/meson.build \
  +      --replace "[ 'cgl_epoxy_api', [ 'cgl_epoxy_api.c' ] ]," ""
  +  '';
  +
     # tests are running from version 1.5.9
     doCheck = true;
   
  
positive.code:   inherit (lib) getLib optional optionalString;
  
  in
  stdenv.mkDerivation (rec {
    pname = "libepoxy";
    version = "1.5.9";
  
  
negative.code:     maintainers = with maintainers; [ goibhniu erictapen ];
      platforms = platforms.unix;
    };
  }
  