installing gtk

I'm having an issue with the gtk+ configure script recognizing my XFree86 libraries. I get this error when I run the compiler.

checking for IceConnectionNumber in -lICE... no
checking for XOpenDisplay in -lX11... no
configure: error: *** libX11 not found. Check 'config.log' for more details.
[nachobel@taco gtk+-1.2.10]$


I don't know what to do.

help?