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

Clarify the meaning of a test.

Rather than using err() if either of two failure conditions
fires (which can produce spurious error messages), just use
errx() if the one condition that really matters fires.

In practice, this single test is enough to detect the failure
mode we're looking for (kqueue being inherited across fork).

Approved by: mentor (rwatson), re (Capsicum blanket)
Sponsored by: Google Inc

Ensure that kqueue is not inherited across fork().

Modify the existing unit test (from libkqueue) which already exercises process events via
fork() and kill(). Now, the child process simply checks that the 'kqfd' descriptor is invalid.

Some minor modifications were required to make err() work correctly. It seems that this test
was imported using the output of a configure script, but config.h was not included in key
places, nor was its syntax correct (need '#define HAVE_FOO 1' rather than '#define HAVE_FOO').

Finally, change main() to run the "proc" suite by default, but widened the '#if TODO' in
proc.c to include the non-functioning test event_trigger().

Approved by: mentor (rwatson), re (Capsicum blanket)
Sponsored by: Google Inc

Merge libkqueue test suite through r119

Submitted by: Mark Heily <mark@heily.com>

Add Mark Heily's libkqueue test suite as a general kqueue test suite to
tools/regression. It tests a number of aspects of kqueue behavior,
although not all currently pass (possibly bugs in the test suite?).

Submitted by: Mark Heily <mark at heily.com>
Obtained from: svn://mark.heily.com/libkqueue/trunk/test (r114)