Fix FreeBSD failure with recursive malloc call.

Fix FreeBSD failure with recursive malloc call.

* mf-hooks1.c (malloc, calloc, realloc, free,
__mf_wrap_alloca_indirect): Call BEGIN_MALLOC_PROTECT before calling
the real routines, and END_MALLOC_PROTECT afterwards.
* mf-impl.h (enum __mf_state_enum): Expand comment.  Add in_malloc.
(BEGIN_PROTECT): Handle in_malloc state.
(BEGIN_MALLOC_PROTECT, END_MALLOC_PROTECT): New.
* testsuite/libmudflap.c/hook2-allocstuff.c: New.

From-SVN: r103256