has a variable called ARCHPREFIX but it is never saved in Config/Config_heavy. EU::MM would actually be getting the "as" value from Config_heavy.pl if "as" would exist in the future. So its a p5p change which means "as" would become available in the next major release. It isn't really a EUMM change unless EUMM will test perl versions, and if that perl doesn't have "as" in %Config then special case if (/gcc$/ && /^(.+)gcc$/), and add that prefix to the future $(AS).