[gtkmm] Newbie Question: How to set PKG-CONFIG_PATH?

[Greg Yasko <ryasko gator net>]

I get the below errors when trying to install gtkmm-2.2.1 (running
./configure) on Red Hat 9. Note I've installed libsigc++ already and
sigc++-1.2.pc lives in
/usr/local/lib/pkgconfig/

//*****************************************************************

checking for sigc++-1.2 >= 1.2.0 glib-2.0 >= 2.2.0 gobject-2.0 >= 2.2.0
gmodule-2.0 >= 2.2.0... Package sigc++-1.2 was not found in the
pkg-config search path.
Perhaps you should add the directory containing `sigc++-1.2.pc'
to the PKG_CONFIG_PATH environment variable
No package 'sigc++-1.2' found
 
configure: error: Library requirements (sigc++-1.2 >= 1.2.0 glib-2.0 >=
2.2.0 gobject-2.0 >= 2.2.0 gmodule-2.0 >= 2.2.0) not met; consider
adjusting the PKG_CONFIG_PATH environment variable if your libraries are
in a nonstandard prefix so pkg-config can find them.

//******************************************************************

So how do I set the PKG_CONFIG_PATH???

I've tried export PATH="usr/local/lib/pkgconfig/sigc++-1.2.pc:$PATH";

When searching google about setting Linux paths I find nothing relevant.

Thanks in advance.

-Greg Yasko