- 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

Bump shared libraries version numbers in preparation for 9.0.
This time, only libraries which ABI has been changed compared to
stable/8, are bumped.

ABI analysis done by: Gleb Kurtsou
Approved by: re (kensmith)

Spelling fixes.

mdoc policing: use consistent section ordering, fix quotes and trailing
whitespace

Approved by: rpaulo

Import the librtld_db library. This is needed by userland DTrace.
This is not yet enabled in the build because I also need to import a new
version of libproc.

Sponsored by: The FreeBSD Foundation