glib-2.0.pc
installs to
/prefix/lib/pkgconfig
you have to actually explain what you have done and if you installed glib-2.4.7
and if so exactly how and with exact package names and commands before anyone can help you..
we are short on our claravoiant capacities today..
glib src tarball comes with "glib-2.0.pc.in" which is a script used to dynamically create glib-2.0.pc at compile time AND THEN INSTALL IT in /prefix/lib/pkgconfig default is /usr/local/lib/pkgconfig