on the stack instead of mallocing the list and move the APIs from libpthread
to libc so that they can be used inside libc.
Note: the standard was explicitly written to permit/support this
"macro with unmatched brace" style and it's what basically everyone
else already does.  We xor the info with random cookies with a
random magic to detect/trip-up overwrites.
Major bump to both libc and libpthread due to the API move.
ok mpi@