make: *** [all] Error 2
 * ERROR: x11-libs/libdrm-2.4.25 failed (compile phase):
 *   emake failed
 *
 * If you need support, post the output of 'emerge --info =x11-libs/libdrm-2.4.25',
 * the complete build log and the output of 'emerge -pqv =x11-libs/libdrm-2.4.25'.
 * The complete build log is located at '/var/tmp/portage/x11-libs/libdrm-2.4.25/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/x11-libs/libdrm-2.4.25/temp/environment'.
 * S: '/var/tmp/portage/x11-libs/libdrm-2.4.25/work/libdrm-2.4.25'

>>> Failed to emerge x11-libs/libdrm-2.4.25, Log file:

>>>  '/var/tmp/portage/x11-libs/libdrm-2.4.25/temp/build.log'

 * Messages for package x11-libs/libdrm-2.4.25:

 * QA: CONFIGURE_OPTIONS are deprecated. Please migrate to XORG_CONFIGURE_OPTIONS to preserve namespace.
 * ERROR: x11-libs/libdrm-2.4.25 failed (compile phase):
 *   emake failed
 *
 * If you need support, post the output of 'emerge --info =x11-libs/libdrm-2.4.25',
 * the complete build log and the output of 'emerge -pqv =x11-libs/libdrm-2.4.25'.
 * The complete build log is located at '/var/tmp/portage/x11-libs/libdrm-2.4.25/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/x11-libs/libdrm-2.4.25/temp/environment'.
 * S: '/var/tmp/portage/x11-libs/libdrm-2.4.25/work/libdrm-2.4.25'

 * GNU info directory index is up-to-date.
localhost pottzie # emerge -uND world
--- Invalid atom in /etc/portage/package.use: update_config=1
--- Invalid atom in /etc/portage/package.use: ap_scan=1
--- Invalid atom in /etc/portage/package.use: ctrl_interface=DIR=/var/run/wpa_supplicant


Then farther down:


 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (sys-libs/talloc-2.0.5, ebuild scheduled for merge) pulled in by
    sys-libs/talloc required by (media-libs/mesa-7.10.2-r1, ebuild scheduled for merge)


For more information about Blocked Packages, please refer to the following
section of the Gentoo Linux x86 Handbook (architecture is irrelevant):

http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?full=1#blocked