MFC r312332,r312446,r312451:

r312332:

Use SRCTOP where possible and use :H to manipulate .CURDIR to get rid of
unnecessarily long relative path .PATH values with make

r312446 (by emaste):

libc: remove reference to nonexistent lib/locale directory

As far as I can tell this was introduced in r72406 and updated in several
subsequent revisions, but the lib/locale directory it referenced never
existed.

r312451:

Replace dot-dot relative pathing with SRCTOP-relative paths where possible

This reduces build output, need for recalculating paths, and makes it clearer
which paths are relative to what areas in the source tree. The change in
performance over a locally mounted UFS filesystem was negligible in my testing,
but this may more positively impact other filesystems like NFS.

LIBC_SRCTOP was left alone so Juniper (and other users) can continue to
manipulate lib/libc/Makefile (and other Makefile.inc's under lib/libc) as
include Makefiles with custom options.

Discussed with: marcel, sjg

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Update our stub resolver to final version of libbind.

Obtained from: ISC

Replace use of ${.CURDIR} by ${LIBC_SRCTOP} and define ${LIBC_SRCTOP}
if not already defined. This allows building libc from outside of
lib/libc using a reach-over makefile.

A typical use-case is to build a standard ILP32 version and a COMPAT32
version in a single iteration by building the COMPAT32 version using a
reach-over makefile.

Obtained from: Juniper Networks, Inc.

Upgrade res_update(3) and the friends to BIND9's one excluding TSIG
support.

X-MFC after: never

It's not enough to provide symbol map files; you also have to add them
to ${SYM_MAPS}. This unbreaks world with SYMVER_ENABLED.

Pointy hat to: ume

- Merge our local changes.
- Exclude unnecessary functions for us.