- 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

Replace our version of the pwcache(3) API with NetBSD's implementation.

This adds two features:
* uid_from_user() and gid_from_group() as the reverse of user_from_uid()
and groups_from_gid().
* pwcache_userdb() and pwcache_groupdb() which allow alternative lookup
functions to be used. For example lookups from passwd and group
databases in a non-standard location.

Vendor import of NetBSD's pwcache(3) as of 2012-10-05