- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

NODOCCOMPRESS -> NO_DOCCOMPRESS
NOINFO -> NO_INFO
NOINFOCOMPRESS -> NO_INFOCOMPRESS
NOLINT -> NO_LINT
NOPIC -> NO_PIC
NOPROFILE -> NO_PROFILE

For variables that are only checked with defined(), don't provide
any fake value.

Avoid linting GNU contrib'ed stuff, even if the build engineer asked
for it (via WANT_LINT). It's Just Too Noisy.