Log Message:
mk/autoconf.mk and mk/automake.mk have been removed.  Replace their
usage with USE_TOOLS and any of "autoconf", "autoconf213", \ 
"automake"
or "automake14".  Also, we don't need to call the auto* tools via
${ACLOCAL}, ${AUTOCONF}, etc., since the tools framework takes care
to symlink the correct tool to the correct name, so we can just
use aclocal, autoconf, etc.  (hi jlam!)