Did you tried to use './configure' with options to help the script to find the include files needed?
I.e.: ./configure --with-pango=/usr/local/pango --with-xft=/usr/X11R6/lib/Xft ...
The above atributes that i gave maybe not be the same used by configure script of gtk, then, look the options running './configure --help'...
If you can't find a option, try to look the config.log file. It is created in the same directory of configure script. Go to the last lines of this file and try to find some error message(s) indicating the problem.
I hope that it help you...
>> Paulo Oliveira Filho
>> Developer / Administrator
>> TiSC Informatica - Brazil