Autoconf not finding pkg-config on OSX? An Easy fix

I've run into this a couple times lately so it's worth noting for others.  aclocal only searches /usr/share/aclocal by default.  This poses a problem because our pkg-config is in /usr/local, but there's an easy fix.  Create a new file named /usr/share/aclocal/dirlist with a line for each additional directory you want to search.  In our case just /usr/local/share/aclocal.  Presto, now autoconf can find pkg-config's macros.