[sigc] Libtool library used but `LIBTOOL' is undefined

[Murray Cumming <murrayc murrayc com>]

In jhbuild, I can't build libsigc++ 2 from cvs, because it fails like
so:
Building makefiles.
sigc++/Makefile.am:70: Libtool library used but `LIBTOOL' is undefined
sigc++/Makefile.am:70:
sigc++/Makefile.am:70: The usual way to define `LIBTOOL' is to add
`AC_PROG_LIBTOOL'
sigc++/Makefile.am:70: to `configure.ac' and run `aclocal' and
`autoconf' again.

I build libsigc++ from cvs every couple of weeks, so this is probably a
recent change in libsigc++ or the autotools that jhbuild installs.
Ideas?

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com