After upgrading to xorg-x11-7.0-r1 emacs is unable to start up using the X windows system. The following error message appears: undefined color: black Portage 2.1-r1 (default-linux/x86/no-nptl, gcc-3.4.6, glibc-2.3.6-r4, 2.6.16-gentoo-r12 i686) ================================================================= System uname: 2.6.16-gentoo-r12 i686 Intel(R) Pentium(R) 4 CPU 2.40GHz Gentoo Base System version 1.6.15 app-admin/eselect-compiler: [Not Present] dev-lang/python: 2.4.3-r1 dev-python/pycrypto: 2.0.1-r5 dev-util/ccache: [Not Present] dev-util/confcache: [Not Present] sys-apps/sandbox: 1.2.12 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-r2 sys-devel/binutils: 2.16.1-r3 sys-devel/gcc-config: 1.3.13-r3 sys-devel/libtool: 1.5.22 virtual/os-headers: 2.6.11-r2 ACCEPT_KEYWORDS="x86" AUTOCLEAN="yes" CBUILD="i686-pc-linux-gnu" CFLAGS="-O3 -march=pentium4 -fomit-frame-pointer" CHOST="i686-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/3.5/env /usr/kde/3.5/share/config /usr/kde/3.5/shutdown /usr/share/X11/xkb /usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/share/texmf/xdvi/" CONFIG_PROTECT_MASK="/etc/env.d /etc/env.d/java/ /etc/gconf /etc/java-config/vms/ /etc/revdep-rebuild /etc/terminfo" CXXFLAGS="-O3 -march=pentium4 -fomit-frame-pointer" DISTDIR="/usr/portage/distfiles" FEATURES="autoconfig distlocks metadata-transfer sandbox sfperms strict" GENTOO_MIRRORS="http://distfiles.gentoo.org http://distro.ibiblio.org/pub/linux/distributions/gentoo" LANG="de_DE" LINGUAS="de" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_RSYNC_OPTS="--recursive --links --safe-links --perms --times --compress --force --whole-file --delete --delete-after --stats --timeout=180 --exclude='/distfiles' --exclude='/local' --exclude='/packages'" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" SYNC="rsync://rsync.gentoo.org/gentoo-portage" USE="x86 X alsa apm arts avi berkdb bitmap-fonts cdr cli crypt cups dlloader dri dvd eds emboss encode foomaticdb fortran gdbm gif gimp gpm gstreamer gtk2 imlib ipv6 isdnlog jpeg kde libg++ libwww mad mikmod motif mp3 mpeg ncurses nls no-seamonkey nsplugin ogg opengl oss pam pcre pdflib perl png pppd python qt qt3 qt4 quicktime readline reflection sdl session spell spl ssl tcpd truetype truetype-fonts type1-fonts vorbis xml xmms xorg xv zlib elibc_glibc input_devices_keyboard input_devices_mouse input_devices_evdev kernel_linux linguas_de userland_GNU" Unset: CTARGET, EMERGE_DEFAULT_OPTS, INSTALL_MASK, LC_ALL, LDFLAGS, PORTAGE_RSYNC_EXTRA_OPTS, PORTDIR_OVERLAY
Did you try to remerge Emacs? Did you run revdep-rebuild? Which version of Emacs?
Remove RgbPath line from your xorg.conf
The emacs version is 21.4-r3. I have remerged emacs several times, but have not tried revdep-rebuild. After removing RgbPath from xorg.conf everything works fine.