I have not used Redhat for years now but perhaps you have a glib-devel package that doesn't match the actual version of glib installed?
The should be a Pango RPM or two as well. Building some libraries from source and installing other related ones as RPM packages is probably like asking for trouble and dependancy problems later on.
An alternate way of getting around this is installing Garnome
or something similar for an alternate set of libraries and programs. I have done this several times on Debian machines (where desktop software releases usually lags behind a lot in the stable distribution) to provide an up-to-date desktop without interfering with the packages provided by the distribution. Install it to, say, /usr/local/garnome, and when building other programs from source specify /usr/local/garnome as the prefix and set LD_LIBRARY_PATH to include the lib subdirectory of the Garnome base directory to provide access to the locally built libs.