Gentoo glibc failed

Problem Description

 during emerge update the following failure occured:

   gentoo sys-libs/glibc-2.12.2 failed 

    emerge sys-devel/gcc

Gentoo GCC Upgrade

 # emerge -u gcc
 # gcc-config -l
 [1] i686-pc-linux-gnu-4.4.5 *
 [2] i686-pc-linux-gnu-4.5.3
 # gcc-config 2
 # env-update && source /etc/profile
 # emerge --oneshot libtool

recommendation ... before emerge -uavND world

 emerge -e --quiet system