args: ( args.mkDerivationByConfiguration { flagConfig = { mandatory = { buildInputs = [ "perl" ]; }; # many options I don't know wether they should be default .. }; extraAttrs = co : { name = "squid-2.6-stable"; src = args.fetchurl { url = http://www.squid-cache.org/Versions/v2/2.6/squid-2.6.STABLE16.tar.bz2; sha256 = "1iv21a4cl74bqzrk07l0lbzlq3n9qpd0r31fgsjv2dsabj46qc4y"; }; meta = { description = "http-proxy"; homepage = "http://www.squid-cache.org"; license = "GPL2"; }; }; } ) args