Yum install zlib-devel, should solve this.
You can post installation related stuff on Xen user mailing list.
From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Phil Winterfield (winterfi)
Sent: Friday, August 08, 2008 9:44
AM
To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] can't find
X11 headers
I am getting this error when I build with CentOS5.1 and
xen-unstable.hg c/s18242. Can someone tell the step(s) to remedy it?
Checking check_x11_devel:
*** check_x11_devel FAILED: can't find X11 headers