Libtool library used but 'LIBTOOL' is undefined

[Bruce Korb]

automake is trying to tell me something, but I cannot make out exactly what.
The literal meaning of the messages is pretty clear, but what they caution
about are things that appear to me to be correct.

> autoreconf --force --install --verbose --symlink
> autoreconf: Entering directory `.'
> autoreconf: configure.ac: not using Gettext
> autoreconf: running: aclocal --force -I m4
> autoreconf: configure.ac: tracing
> autoreconf: configure.ac: not using Libtool
> autoreconf: running: /usr/bin/autoconf --force
> autoreconf: running: /usr/bin/autoheader --force
> autoreconf: running: automake --add-missing --force-missing
> configure.ac:30: installing './compile'
> configure.ac:11: installing './config.guess'
> configure.ac:11: installing './config.sub'
> configure.ac:23: installing './install-sh'
> configure.ac:23: installing './missing'
> doc/Makefile.am:42: installing 'doc/texinfo.tex'
> lib/Makefile.am:31: error: Libtool library used but 'LIBTOOL' is undefined
> lib/Makefile.am:31:   The usual way to define 'LIBTOOL' is to add 'LT_INIT'
> lib/Makefile.am:31:   to 'configure.ac' and run 'aclocal' and 'autoconf' 
> again.
> lib/Makefile.am:31:   If 'LT_INIT' is in 'configure.ac', make sure
> lib/Makefile.am:31:   its definition is in aclocal's search path.
> lib/Makefile.am: installing './depcomp'
> autoreconf: automake failed with exit status: 1

Yes, I see the
  ``If 'LT_INIT' is in 'configure.ac', make sure its
    definition is in aclocal's search path.''
stuff, but if I google the string, I just get advice
to add LT_INIT to my configure.ac file.  Pretty useless.
If someone would just be kind enough to adjust the message
so I can determine how to put the thing into the aclocal search
path, I would be really happy.  Thank you!  Regards, Bruce

P.S. it is *not* defined in the m4 subdirectory, which
is created by the gnulib-tool script.