AIX atomicity.h support

[David Edelsohn]

>>>>> Benjamin Kosnik writes:

Ben> Is there anyway you can post an integrated patch that takes 
Ben> into account all the things you've done, and includes a ChangeLog entry, 
Ben> please?

	This file and some configure stuff are the only things that I have
done.  Everything else is unacceptable kludges.

	I am waiting for a response on how to handle libtool brain damage,
POSIX brain damage in libio, ctype brain damage, pthread brain damage,
etc.

David