libstdc++-v3 won't build on AIX 4.1 any more (3.0 branch)

[Alexandre Oliva]

linking /home/lsd/oliva/src/tool/egcs/libstdc++-v3/config/os/generic/bits/atomicity.h to include/bits/atomicity.h
configure: error: /home/lsd/oliva/src/tool/egcs/libstdc++-v3/config/os/generic/bits/atomicity.h: File not found
make[1]: *** [configure-target-libstdc++-v3] Error 1

Indeed, config/os/generic/bits/atomicity.h doesn't exist.

I haven't tested mainline, as this machine takes days to get to this
point of the build, but this file is missing in mainline too :-(

I suppose the case that matches aix* to define ATOMICITYH should be
made stricter so as to match only AIX 4.3 or newer, like the case that
sorts os_include_dir does?

Ok to install?