- 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

Revert to conservative defaults. WITH_PROFILE is a default now.

NO_PROFILE overrides in Makefile.inc1 and bsd.own.m are left intact
so that the reversal to the WITHOUT_PROFILE will be easier in future.

Turn off profiled libs build by default.
Can be enabled back using WITH_PROFILE=yes in /etc/src.conf

Prepare to autogenerate the src.conf(5) manpage.