rec {
   version="2.16";
   name="asymptote-2.16";
   hash="1yj8dx320s1ypqbpb2116y4kkc8lwg5q4d49n992ds3g59w98djj";
   url="http://downloads.sourceforge.net/project/asymptote/${version}/asymptote-${version}.src.tgz";
   advertisedUrl="http://downloads.sourceforge.net/project/asymptote/2.16/asymptote-2.16.src.tgz";
}