I have tried compiling several source codes, and always get an error such as "cant find x includes". I have also seen one that said "missing kdelibs" or something of the like. I have the development packages from redhat installed, c compilers, make, the works. Maybe a problem with path settings? Oh and I am running redhat 8.

Thanks

I'd have to look at what RedHat's development package includes. My gut tells me it includes just the kernel source. It looks like you're trying to compile some GUI-based applications. The first error you mention:
Is telling you that the compiler can't find certain X Windows header files. You may need to download the XFree86 source and unpack it for that compile to work.

Your second error:
Is telling you that certain KDE libraries are missing. When you installed RedHat, did you install the KDE environment, Gnome environment, or both? As far as I know applications developed for KDE won't run in Gnome (and vice versa). Don't take my word for it though.

I believe that the basic redhat development package includes c libraries, compilers, make/ automake etc., then there were kde specific development packages, which i dont have installed. maybe thats the problem. I am running only kde by the way, and the things i have tried to compile were meant to work on kde. I will try XFree86 though.

I've never Used RedHat but I do compile everything from source and I try "ldconfig" in a root terminal first. Then a "whereis" before jumping to download a bunch of stuff you already have but it wasn't linked correctly. {KDE libs are in opt/kde/lib)

The Red Hat packages under the development section include three options you probably want installed:[list=1][*]Development Tools[*]X Software Development[*]KDE Software Development[/list=1]
I you added these post-install then you probably do need to run "ldconfig" as Allen614 suggested. Go ahead and run it anyway... it won't hurt anything.

Side note: KDE runs on top of X. I didn't mean to confuse you about XFree86... that's just the windowing system that window managers (like KDE and Gnome) use to actually display their windows, dialogs, and the like.

Now, if all of that stuff is installed and you still get compile errors, then you'll have to do some reading. The software you're trying to compile should come with some documentation about what libraries it depeds on. Get a list of them and verify they actually are on the system you can use:
updatedb
locate <insert library name here>

You only need to run updatedb once, and that updates the database that locate uses to find files. Then fire off as many locate commands as needed. Again, as Allen614 said, KDE libraries should be in /opt/kde/lib.

If you have all the libraries, then read the INSTALL documentation. It may discuss options to pass to the configure script (such as being able to specify a "libdir" path). You may need to do that if your libraries are in a different directory than the default.