The m4 man page doesn't indicate any default include path, or file or
environment variable to control one.  Is there really no default?  

Running autoconf, I get this message:

"
Please add the files
  codeset.m4 gettext.m4 glibc21.m4 iconv.m4 isc-posix.m4 lcmessage.m4
  progtest.m4
from the /usr/pkg/share/aclocal directory to your autoconf macro directory
or directly to your aclocal.m4 file.
"

What would my "autoconf macro directory" be?  I'm running 1.6.

Thanks.

--jkl