Requested to file this bug by Gentoo dev Donnie Berkholz.  The link to the
Gentoo bug is in the URL field.  On a clean installation of modular Xorg with no
previous installation of X, I was unable to compile xorg-server without first
installing the Xtrap and panoramix extensions.  It fails because of missing
header files supplied by these extensions.  It succeeds after adding these. 
They aren't listed in the REQUIRED_MODULES variable in xorg-server's
configure.ac, but they appear to be needed.  

I'm only trying to install the most basic xorg-server, so on Gentoo I have all
the possible USE flags for that package disabled.

Here's my system info from the 'emerge info' command, let me know if any other
info is needed:

Portage 2.0.51.22-r1 (default-linux/x86/2005.0, gcc-3.4.4, glibc-2.3.5-r1,
2.6.12-gentoo-r5 i686)
=================================================================
System uname: 2.6.12-gentoo-r5 i686 AMD Athlon(tm) 64 Processor 3400+
Gentoo Base System version 1.6.12
ccache version 2.4 [enabled]
dev-lang/python:     2.3.4-r1
sys-apps/sandbox:    1.2.10
sys-devel/autoconf:  2.13, 2.59-r7
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.6
sys-devel/binutils:  2.16.1
sys-devel/libtool:   1.5.18-r1
virtual/os-headers:  2.6.8.1-r4
ACCEPT_KEYWORDS="x86 ~x86"
AUTOCLEAN="yes"
CBUILD="i686-pc-linux-gnu"
CFLAGS="-O1 -march=athlon-xp -pipe"
CHOST="i686-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.4/env
/usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config
/usr/share/config /var/qmail/control"
CONFIG_PROTECT_MASK="/etc/env.d /etc/gconf /etc/terminfo /etc/env.d"
CXXFLAGS="-O1 -march=athlon-xp -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig ccache distlocks sandbox sfperms strict"
GENTOO_MIRRORS="http://mirror.datapipe.net/gentoo http://gentoo.seren.com/gentoo"
MAKEOPTS="-j2"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/fluidportage /usr/local/portage"
SYNC="rsync://rsync.us.gentoo.org/gentoo-portage"
USE="x86 3dnow X a52 aac acpi aim alsa arts audiofile avi bash-completion berkdb
bidi bitmap-fonts cairo cdda cddb cdio cjk crypt cups dga divx4linux dlloader
dpms dvd dvdr dvdread eds encode fam ffmpeg foomaticdb fortran freetype gdbm gif
glitz gpm gstreamer gtk gtk2 hal imlib jikes jpeg kde kdeenablefinal kdexdeltas
libg++ libwww lzo mad mikmod mmap mmx mmxext mng motif moznomail mp3 mpeg
ncurses nls nptl nptlonly ogg oggvorbis openal opengl oss pam pdflib perl png
pnp ppds python qt quicktime rdesktop readline real sdl sndfile spell sse sse2
ssl svg tcpd tidy tiff truetype truetype-fonts type1-fonts userlocales vorbis
win32codecs wxwindows xml2 xmms xprint xscreensaver xv xvid zlib userland_GNU
kernel_linux elibc_glibc"
Unset:  ASFLAGS, CTARGET, LANG, LC_ALL, LDFLAGS, LINGUAS