root@eclipse: $  emerge -av compiz-fusion

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  N    ] x11-wm/compiz-9999  USE="dbus kde svg -fuse -gnome -gtk" 0 kB [1]
[ebuild  N    ] x11-libs/compiz-bcop-9999  0 kB [1]
[ebuild     U ] x11-wm/emerald-9999 [0.2.1] USE="(-debug%)" 0 kB [1]
[ebuild  N    ] x11-libs/libcompizconfig-9999  0 kB [1]
[ebuild  N    ] x11-plugins/compiz-fusion-plugins-main-9999  0 kB [1]
[ebuild  N    ] x11-libs/compizconfig-backend-kconfig-9999  USE="arts xinerama -debug" 0 kB [1]
[ebuild  N    ] x11-plugins/compiz-fusion-plugins-extra-9999  0 kB [1]
[ebuild  N    ] dev-python/compizconfig-python-9999  0 kB [1]
[ebuild     U ] x11-themes/emerald-themes-9999 [0.2.1] 0 kB [1]
[ebuild  N    ] x11-apps/ccsm-9999  0 kB [1]
[ebuild  N    ] x11-wm/compiz-fusion-9999  USE="kde -gnome" 0 kB [1]

Total: 11 packages (2 upgrades, 9 new), Size of downloads: 0 kB
Portage overlays:
 [1] /usr/portage/local/layman/xeffects
 [2] /usr/local/overlays/crossdev

Would you like to merge these packages? [Yes/No]
>>> Verifying ebuild Manifests...

>>> Emerging (1 of 11) x11-wm/compiz-9999 to /
 * checking ebuild checksums ;-) ...                                                                                                   [ ok ]
 * checking auxfile checksums ;-) ...                                                                                                  [ ok ]
 * checking miscfile checksums ;-) ...                                                                                                 [ ok ]
>>> Unpacking source...
 * git update start -->
 *    repository: git://anongit.freedesktop.org/git/xorg/app/compiz
 *    local clone: /usr/portage/distfiles/git-src/compiz
 *    committish: master
tar: .cvsignore: time stamp 2007-07-28 19:34:38 is 11120.179413 s in the future
tar: AUTHORS: time stamp 2007-07-28 19:34:38 is 11120.179216 s in the future
tar: COPYING: time stamp 2007-07-28 19:34:38 is 11120.179083 s in the future
tar: COPYING.GPL: time stamp 2007-07-28 19:34:38 is 11120.178865 s in the future
tar: COPYING.LGPL: time stamp 2007-07-28 19:34:38 is 11120.178634 s in the future
tar: COPYING.MIT: time stamp 2007-07-28 19:34:38 is 11120.178495 s in the future
tar: ChangeLog: time stamp 2007-07-28 19:34:38 is 11120.177626 s in the future
tar: INSTALL: time stamp 2007-07-28 19:34:38 is 11120.177474 s in the future
tar: Makefile.am: time stamp 2007-07-28 19:34:38 is 11120.177325 s in the future

...
tar: src/texture.c: time stamp 2007-07-28 19:34:38 is 11120.062091 s in the future
tar: src/window.c: time stamp 2007-07-28 19:34:38 is 11120.060416 s in the future
tar: src: time stamp 2007-07-28 19:34:38 is 11120.060283 s in the future
>>> Unpacked to /var/tmp/portage/x11-wm/compiz-9999/work/compiz-9999
>>> Source unpacked.
>>> Compiling source in /var/tmp/portage/x11-wm/compiz-9999/work/compiz-9999 ...
 * Applying compiz-no-gconf.patch ...                                                                                                  [ ok ]
 * Running eautoreconf in '/var/tmp/portage/x11-wm/compiz-9999/work/compiz-9999' ...
 * Running aclocal ...                                                                                                                 [ ok ]
 * Running libtoolize --copy --force --automake ...                                                                                    [ ok ]
 * Running aclocal ...                                                                                                                 [ ok ]
 * Running autoconf ...                                                                                                                [ !! ]

 * Failed Running autoconf !
 *
 * Include in your bugreport the contents of:
 *
 *   /var/tmp/portage/x11-wm/compiz-9999/temp/autoconf-29715.out


!!! ERROR: x11-wm/compiz-9999 failed.
Call stack:
  ebuild.sh, line 1621:   Called dyn_compile
  ebuild.sh, line 973:   Called qa_call 'src_compile'
  ebuild.sh, line 44:   Called src_compile
  compiz-9999.ebuild, line 54:   Called eautoreconf
  autotools.eclass, line 95:   Called eautoconf
  autotools.eclass, line 165:   Called autotools_run_tool 'autoconf'
  autotools.eclass, line 218:   Called die

!!! Failed Running autoconf !
!!! If you need support, post the topmost build error, and the call stack if relevant.
!!! A complete build log is located at '/var/tmp/portage/x11-wm/compiz-9999/temp/build.log'.

!!! This ebuild is from an overlay: '/usr/portage/local/layman/xeffects'

~
root@eclipse: $  cat /var/tmp/portage/x11-wm/compiz-9999/temp/autoconf-29715.out
***** autoconf *****

configure.ac:160: error: possibly undefined macro: AM_GCONF_SOURCE_2
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.