it in.
Some review from -hackers (some time ago), and I think the best way to
get this improved (if it needs improving) or updating, is to bring it in.
PR: docs/12557
Submitted by: Tim Singletary <tsingle@triana.gsfc.nasa.gov>
so that all these makefiles can be used to build libc_r too.
Added .if ${LIB} == "c" tests to restrict man page builds to libc
to avoid needlessly building them with libc_r too.
Split libc Makefile into Makefile and Makefile.inc to allow the
libc_r Makefile to include Makefile.inc too.