Re: AIX atomicity.h support

[David Edelsohn <dje at watson dot ibm dot com>]

	The issue with threading is that AIX supports pthreads, but AIX 4
has pthread support in a separate library without even the symbol stubs in
the regular library.  This means that AIX pthread support needs to be
multilib (which it is with GCC) and v3 needs to select threads-posix.h
versus threads-no.h depending on a macro definition (as I have done with
gthr-aix.h and the old libstdc++).  v3 configuration has many more
"threads" variable floating around and it is taking me a lot of time to
figure out the interactions and dependencies to get the compile-dependent
pthreads behavior AIX uses.

	CVS G++ and AIX ld have been working fine for me.  It builds a
working, shared library version of the old libstdc++.

	With the latest v3 snapshot, I ended up with a Makefile with the
@MAINTAINER_MODE@ variable unsubstituted, and the math library is
complaining about FINITE_P and INFINITE_P macros undefined.  I am trying
to track these down, but it is laborious.  The length of time that v3
takes to configure is pretty startling; it seems that it should be able to
recognize which transcendendal functions are available more quickly.

	I will send the current form of my patches in the next message.

David