and that will set LIBS as desired for the top level Makefile.PL. But the argument doesn't get passed on to any Makefile.PL in the distro's sub directories.
What do I need to do to ensure that the subdir Makefile.PL's also receive that command line argument ?
(This relates to one of my own modules, so there's no problem with making modifications to the existing Makefile.PL's if that's what's needed. It's just a matter of finding out what needs to be done. Perhaps someone knows of a distro that already caters for this.)