FreeBSD 10.0 adaptive mutex with strange mtx_lock value = panic

[Chris Torek]

>I added "options INVARIANTS" to a kernel and recompiled..
>
>Well, I tried to recompile - compiling ends like this:
>
>cam_periph.o: In function `cam_periph_find':
>/usr/src/sys/amd64/compile/DEBUG/../../../cam/cam_periph.c:301:
>undefined reference to `__mtx_assert'
[etc]

The INVARIANTS option requires the INVARIANT_SUPPORT option.

I believe INVARIANTS ought to just automatically turn on
INVARIANT_SUPPORT, really.  But it's pretty minor, once you
know.

Chris