MFC r213241, r213257:

MFC r213241, r213257:
In current code, statically initialized and destroyed object have
same null value, the code can not distinguish between them, to
fix the problem, now a destroyed object is assigned to a non-null
value, and it will be rejected by some pthread functions.
PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP is changed to number 1, so that
adaptive mutex can be statically initialized correctly.

git-svn-id: svn://svn.freebsd.org/base/stable/8@214371 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f