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

Use panic() (which the environment is required to provide to libstand) to
implement assert() instead of relying on a non-required exit(). The exit()
invocation also did not match the semantics of the exit() routine that
current boot environments happen to require.

PR: kern/144749
Discussed with: bde
MFC after: 1 week

Make the output from assert() look more like the example in the C99
standard.

Requested by: bde

Only provide function information in compile environments that support
the C99 variable __func__ and never for C++. Provide a more meaningful
example in the assert(3) manual.

Reviewed by: asmodai, bde

Add __FBSDID.
Change __assert() function to print failing function name.
This makes us C99 conforming.

Add __FBSDID()s to libstand

Make include file consistent with the rest of libstand.

$Id$ -> $FreeBSD$

Add:
assert()
setjmp()/longjmp()
vsprintf()