- 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

Const poisoning.

Add __FBSDID()s to libutil

Fix problems people were having with large -O levels with GCC and
getting libutil/libcrypt to work properly. I've determined that GCC
thinks it can inline all functions, including weak-symboled ones, if
it feels like it.

Create a new stub.c and move any stubs there to prevent inlining.
Thanks to jdp and William S. Duncanson for helping me finally find the
problem.

Add weak symbol pragma for crypt_set_format().

Approved by: green

Stick login_setcryptfmt() in its own file to make pulling in of
-lcrypt only happen if truly necessary.