[Kwintv] X includes

[Johannes Lebek]

Hi there,

I try to build kwintv3. I was following the "CVS Information" on 
www.kwintv.org. My System is a RedHat 9 with KDE 3.1. KDE and QT are not 
located at /opt, but /usr/lib. Additionally, my "kde3" directory does 
not contain any "lib" or "bin" directory, but the file count in that 
directory exceeds 700.

I get an error message at step "./configure", that reads:

checking for X... configure: error: Can't find X includes. Please check 
  your installation and add the correct paths!

Where do I find these X includes?
Any help is greatly appreciated.

Johannes