Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

ANSIfy, WARNSify, CONSTify. Bit of style(9)-ify.

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.