[Python-Dev] Updating to autoconf 2.5x

[Skip Montanaro]

    Martin> If all regular editors of configure.in have autoconf 2.5x
    Martin> available, or can install it, I'd propose to bump the AC_PREREQ
    Martin> to 2.50.

I believe 2.50 had serious bugs and was superceded rather quickly by the
autoconf maintainers.  I would vote to boost to 2.52 or above.

Skip