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

Remove various bits of conditional Alpha code and fixup a few comments.

Make tv_sec a time_t on all platforms but alpha. Brings us more in line with
POSIX. This also makes the struct correct we ever implement an i386-time64
architecture. Not that we need too.

Reviewed by: imp, brooks
Approved by: njl (acpica), des (no objects, touches procfs)
Tested with: make universe

Move struct timeval to its own header so that it can be shared between
multiple headers.