Has anyone installed EMBOSS on Red Hat? I'm having trouble with X11, and the installation isn't really helping:

X11 graphics have been selected but no X11 header files have been found.

This error usually happens on Linux/MacOSX distributions where the optional X11 development files have not been installed. On Linux RPM systems this package is usually called something like xorg-x11-proto-devel whereas on Debian/Ubuntu it may be called x-dev. On MacOSX installation DVDs the X11 files can usually be found as an explicitly named optional installation.

What does this mean that I have to do with X11? I think I have an X11 installation

[[lkatz@localhost X11]$ pwd && ll
/etc/X11
total 108
drwxr-xr-x 2 root root 4096 Oct  1  2009 applnk
drwxr-xr-x 2 root root 4096 Feb 18 05:08 fs
drwxr-xr-x 2 root root 4096 Mar 23 15:52 mwm
-rwxr-xr-x 1 root root  947 Oct 13 09:42 prefdm
drwxr-xr-x 2 root root 4096 Oct  1  2009 serverconfig
drwxr-xr-x 2 root root 4096 Oct  1  2009 sysconfig
drwxr-xr-x 2 root root 4096 Feb 18 05:00 twm
lrwxrwxrwx 1 root root   18 Mar 23 15:16 X -> ../../usr/bin/Xorg
drwxr-xr-x 5 root root 4096 Mar 22 15:00 xinit
-rw-r--r-- 1 root root  547 Nov 13  2007 Xmodmap
-rw-r--r-- 1 root root 1784 Mar 23 19:05 xorg.conf
-rw-r--r-- 1 root root 1882 Mar 23 15:38 xorg.conf.backup
-rw-rw-r-- 1 root root 1912 Mar 23 15:47 xorg.conf.backup-nvidia
-rw-r--r-- 1 root root  492 Nov 13  2007 Xresources

[lkatz@localhost X11]$ ll ../../usr/bin/Xorg 
-rws--x--x 1 root root 1945600 Sep  1  2010 ../../usr/bin/Xorg

Thank you for your help.