[XFree86] The GUIness of it all

Ok, so I finally got X compiled (stupid ldconfig) but now I have another problem. I'm trying to install xFCE for a desktop manager, so I'm also trying to compile the GTK (dependency). I've installed all of the _GTK's_ dependencies, but every time I try to run ./configure, it crashes with the

[XFree86] Freaking Compile Error - libpng.so.3

I installed libpng myself [latest stable version, acquired today from libpng.org] but whenever I try to compile XFree86 [also the latest stable version] make exits with an error. The first line in the error is: ../../..exports/bin/xcursorgen: error while loading shared libraries: libpng.so.3: