recent changes to obstacks cause many out of memory failures in M4 master testsuite

[Gary V. Vaughan]

Hi,

To pick up bug fixes in maint.mk required for 'make public-submodule-commit' 
and dependers to work on Mac OS X 10.10, I just tried to update GNU M4's master 
branch to gnulib master HEAD, but that causes a raft of test failures where m4 
bails out with a 'memory exhausted' error before completing the tests.

Bisecting my way to the the first gnulib changeset that causes these failures, 
I landed at:

  bb2ab7e 2014-10-29 14:02 Alan Modra   obstack: 64-bit obstack support, part 2

Which is not surprising as GNU M4 uses GNU obstack extensively throughout.  Any 
revisions prior to that allow m4 to pass it's tests, but I'm afraid I don't 
understand the change well enough to point at the actual root of the issue.  
Hopefully someone here more knowledgable than I will be able to advise.

Cheers,
-- 
Gary V. Vaughan (gary AT gnu DOT org)