Which autoconf for libstdc++

[Ulrich Weigand]

Hello,

I'm trying to regenerate the libstdc++ configure file, but cannot
even reproduce the current file with any autoconf version I have.

doc/install.texi says libstdc++ is supposed to use autoconf-2.57,
but the current configure file says it was generated by 2.58.
However, even if try to regenerate using 2.58, there are still
significant changes to the current file ...

Which autoconf am I supposed to use?

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  weigand@informatik.uni-erlangen.de