I'm having a similar problem...I don't mean to hijack this thread but it's closely related I think. I downloaded gtk+-2.4.3 and did ./configure trying to follow along with the tutorial at
http://www.gtk.org/tutorial/ch-gettingstarted.html but when compiling that simple program it said the gtk.h file didn't exist. I found where it installed the files and simply changed the original #include statement to #include<gtk-2.0/gtk/gtk.h>
Now when I compile, pages and pages of errors fly by, from what I can tell, every gtk*.h file has an error like "field 'scale' has incomplete type" and several syntax errors.
So I searched this site and the ./configure --help and tried doing ./configure -prefix=/usr/include/
I then changed the #include to the original statement, and still get all those errors.
I've been searching for several hours for the answer and haven't found one, so can anybody tell me how to get this working?
Using Gentoo with 2.6 kernel and fluxbox, tried reemerging gtk but that didn't help either.