Problem of installing root at Scientific Linux

hi rooters,
I have a problem when I tried to install root_v4.04.02g at Scientific Linux:

[root@localhost root_v4.04.02g]# ./configure
Configuring for linux
Checking for libX11 … no
configure: libX11 (package x11-devel) MUST be installed
[root@localhost root_v4.04.02g]#

I had install SL with full packages. Does it mean that I have to download a x11-devel package ? Or any other way to solve the problem?

Cheers!

As clearly indicated by the configure message, you must install this package
to work with ROOT and Xwindows under Linux.

Rene