Similar to libexec/, do the same with lib/. Make WARNS=6 the norm and
lower it when needed.
I'm setting WARNS?=0 for secure/. It seems secure/ includes the
Makefile.inc provided by lib/. I'm not going to touch that directory.
Most of the code there is contributed anyway.
preparation for 8.0-RELEASE. Add the previous version of those
libraries to ObsoleteFiles.inc and bump __FreeBSD_Version.
Reviewed by: kib
Approved by: re (rwatson)