- 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

Synchronize with C.msg revision 199083 and improve some existing messages.

Reviewed by: remko
Approved by: remko

- Reenable Native Language Support in libc. This feature was disabled due
to possible breakages in the catalog handling code. Since then, that
code has been replaced by the secure code from NetBSD but NLS in libc
remained turned off. Tests have shown that the feature is stable and
working so we can now turn it on again.

- Add several new catalog files:
- ca_ES.ISO8859-1
- de_DE.ISO8859-1
- el_GR.ISO8859-7 (by manolis@ and keramida@)
- es_ES.ISO8859-1 (kern/123179, by carvay@)
- fi_FI.ISO8859-1
- fr_FR.ISO8859-1 (kern/78756, by thierry@)
- hu_HU.ISO8859-2 (by gabor@)
- it_IT.ISO8859-15
- nl_NL.ISO8859-1 (corrections by rene@)
- no_NO.ISO8859-1
- mn_MN.UTF-8 (by ganbold@)
- sk_SK.ISO8859-2
- sv_SE.ISO8859-1
(The catalogs without explicit source has been obtained from NetBSD.)

Approved by: attilio