Well, I'm really stumped by this one. :P

After getting the "Can't find X includes..." error while compiling, I tried urpmi to install the missing devel packages. I heard of a package called "xorg-x11-devel," so I attempted to install that, but urpmi reported that there was no such package.
I then Googled around a bit and found a package called "libxorg-x11-devel," (not sure if that's even relevant) so I tried to install that. It complained of other missing packages which then led to more dependency problems so I just ditched trying that.

If anyone has any ideas, please help me out. Thanks in advance.

Edit: I'm using Mandrake 10.1 Official by the way.

You need to install your kernel source. Open a console window and type: su <press enter> <input root password> <press enter> now type: urpmi kernel-source <press enter>. When installation has finished type: exit <press enter> to return to normal user mode. That will take care of your X-includes issues.

I installed the kernel sources (2.6.x) with urpmi, but it still gives me that same error.
However, I found some more libxorg-x11 packages in the urpmi repositories, but I'm going through dependency hell right now with these RPMs. Hopefully those will do the trick.

Whoops, double post. Sorry.

This problem relates to the xorg-devel package and nothing to do with the kernel source. The package you need to install is called libxorg-x11-devel. The best way to install it and get all dependenies resolved automatically is to use urpmi. To find out more about urpmi, go to zebulon.org.uk and for instructions on how to set it up go to easyurpmi.