- 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

Allow multiple inclusion of trap.h. This has always been broken, but
until recently never caused problems.

Rework and extend PowerPC headers definitons towards Book-E/e500 CPUs support.

Approved by: cognet (mentor)
Obtained from: Juniper, Semihalf
MFp4: e500