GCC 3.x requires autoconf 2.13

["Gary Funck" <gary at Intrepid dot Com>]

Recently, I needed to make some small modifications to configure.in on a
runtime library we developed that is built with GCC (ie, lives at the same
level as libiberty and libstdc++-v3). I ran autoconf, and it came back with:

configure.in:32: error: defn: undefined macro: _AC_PROG_CC_GNU
aclocal.m4:220: GLIBCPP_CONFIGURE is expanded from...
configure.in:32: the top level

(The output above, in fact comes from running autoconf in the libstdc++-v3
directory, using the GCC version 3.2.3 source baseline,and is the same error
that I was seeing in our library. I'm posting libstdc++-v3 output to
demonstrate that this breaks on the main GCC source baseline, as well as our
own library.)

The lines of interest follow,

in configure.in:
# Runs configure.host and configure.target, as well as finds CC, CXX
# and assorted other critical bits.  Have to run this before the
# GLIBCPP_ENABLE_* macros below.
GLIBCPP_CONFIGURE(.)

in aclocal.m4:
  # Never versions of autoconf add an underscore to these functions.
  # Prevent future problems ...
  ifdef([AC_PROG_CC_G],[],[define([AC_PROG_CC_G],defn([_AC_PROG_CC_G]))])
  ifdef([AC_PROG_CC_GNU],[],[define([AC_PROG_CC_GNU],defn([_AC_PROG_CC_GNU]))])

After some research, and trial and error, I found that this incarnation of
configure.in
doesn't seem to work well with a newer version of autoconf. The version of
autoconf that I used was 2.53. The configure script mentions 2.13 as the
version it was built with. So, I downloaded and a copy of version 2.13 of
autoconf, installed it, and ran it, and it ran without problems.

I was a little suprised by this, because version 2.13 of autoconf is dated Jan.
1999,
and I was unaware there might be dependencies in the current GCC sources to
such an old version of a tool.

Couple of questions:
1) Is this a known problem, expected behavior, and developers are supposed to
user version 2.13 of autoconf if they want to make changes to GCC's
configuration files?

2) Is there some switch setting, environment variable, etc. that I was supposed
to set before running the newer version of autoconf?