The m4 library that is installed by default, sirbarton /var# m4 --version GNU m4 1.4 has a bunch of support macros that autoheader, version sirbarton /var# autoheader --version Autoconf version 2.13 does not like because they use m4_regexp and m4_patsubst. The fix is to sed them out for the suggested replacement, regexp and patsubst.
no real info here ... m4 installs a binary, no support files we've changed our autotools to run newer by default rather than older (meaning 2.59 instead of 2.13) re-open when you've provided actual output of what you're talking about