[Bug boehm-gc/52179] boehm-gc incompatible with aslr on darwin11

[mikestump at comcast dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52179

--- Comment #11 from Mike Stump <mikestump at comcast dot net> 2012-02-23 
04:56:55 UTC ---
Ah, the better way to do that would be to have:

AC_CHECK_FUNCS([pthread_get_stackaddr_np])

in configure.ac, and then just have

#ifdef HAVE_PTHREAD_GET_STACKADDR_NP
#define STACKBOTTOM (ptr_t)pthread_get_stackaddr_np(pthread_self())
#endif

This should cover all the issues with NO_PTHREAD...