In this new build structure we are adding libraries to $LIBS as we add
modules instead of doing an AC_SUBST into the Makefile. One reason for
doing the subst in php3 was to get around the libraries that could not
be included in $LIBS because doing so would mess up the various configure
tests. For example, you can't do a -limap as part of the various simple
configure compile programs because -limap requires a bunch of callback
symbols to be present.
