[RPM] 7.4.1 srpm dies running autoconf

I'm trying to build 7.4.1 using the PGDG srpm. I've resolved the
obvious dependencies, but I keep running into a problem with autoconf.
The error I see comes right after applying patch 8:

Patch #8 (postgresql-7.4.1-com_err.patch):
+ patch -p1 -s
+ aclocal
+ autoconf
/usr/bin/autoconf: /var/tmp/autoconf-root/usr/bin/autom4te: No such file
or directory
/usr/bin/autoconf: exec: /var/tmp/autoconf-root/usr/bin/autom4te: cannot
execute: No such file or directory
error: Bad exit status from /var/tmp/rpm-tmp.53244 (%prep)

Note that I added "aclocal" just as a test (its not in the original spec
file), but the error is the same nonetheless. "autom4te" is installed:

mhammel(tty0)$ locate autom4te
/usr/bin/autom4te

If I run /var/tmp/rpm-tmp.<???> by hand it works. Go figure.

Anyone know why rpm/autoconf is trying to run autom4te from that
directory? Is this a problem with my autoconf version (2.57)? It seems
like it has something to do with how RPM calls autoconf, since I can run
the generated script by hand and it works.

Any pointers greatly appreciated. Thanks.
--
Michael J. Hammel
mhammel(at)rlx(dot)com