gtk problems "help"

["RedHat" <rob@robgraham.net>]

When trying to install gtkmm-1.2.8 by running ./configure on my Redhat 7.3
Valhalla machine
i get this following error message:

checking for libsigc++ - version >= 0.8.5... configure: error: Libsigc++ is
required
to compile Gtk--. If libsigc++ was installed but not found to be sane, most
likely you
have not placed the /usr/local/lib path in the library config file and run
ldconfig.

I've previously installed libsigc++-1.0.3-5.i386.rpm before attempting the
gtkmm install.

Now I'm not sure where the library config file is located and what the
actual name of
it is called. Does anyone have any idea.