maint: licensing conformance follow-up (library->program)
Once we got clarified "GPLv2.1+ -> GPLv2+" (rejecting LGPL
interpretation, cf. e294fa2), we ought to reword "library"
references to say "program", in accordance to the standard
GPLv2 notice.
In the same vein, da90d0b missed an instance of the old FSF
address, so get this resolved as well.