trouble adding new macros to my configure.ac

[Nina Nordstrom]

Hello,
I have an autoconf problem I am trying to solve: Basically I need to add new
macros and use them in configure.ac... specifically, I would like to add a
macro called AX_GCC_ARCHFLAG found in the autoconf macro archive somewhere
in my package and then it in my configure.ac

Problem is, how do I do that? I tried to add this macro (and the
prerequisites) inside aclocal.m4, but it seems aclocal.m4 gets autogenerated
by aclocal whenever autoconf makes the configure script.

Is there a way to keep the macro in a separate file (eg ax_gcc_archflag) in
the same directory as configure.ac and tell that to configure.ac?

Sorry if this is a "newbie" question, I could not find this info in all my
reading and googling..

thanks,
nina