aix4.3 bootstrap fails with snapshot 20000612

[David Edelsohn]

	Actually, I am not sure that this even is a code generation bug.
I just did some divide and conquer debugging because, as Kaveh mentions in
his bug report, GDB is useless after the segfault.  getattr is failing in
gensupport.c:init_md_reader() which calls obstack_init(rtl_obstack) when
the function returns.  I am suspicious that obstack_init() is clobbering
the stack preventing function return and any stackframe traceback.

David