- 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

Match the options of the kernel.

Test both active and non-active cases.

Iterate rather than use recursion. We can blow out the kernel stack if there
is a long chain of fork(2)s.

Support also running a 32-bit test on 64-bit platforms.

Add a regression test for filemon(4) [r236592].