cat /var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/temp/build.log
 * Package:    dev-libs/libmemcached-1.0.17-r1
 * Repository: gentoo
 * Maintainer: robbat2@gentoo.org prometheanfire@gentoo.org
 * USE:        amd64 elibc_glibc kernel_linux libevent userland_GNU
 * FEATURES:   preserve-libs sandbox splitdebug userpriv usersandbox
>>> Unpacking source...
>>> Unpacking libmemcached-1.0.17.tar.gz to /var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/work
>>> Source unpacked in /var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/work
>>> Preparing source in /var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/work/libmemcached-1.0.17 ...
 * Applying libmemcached-1.0.17-gcc4_8.patch ...                                                                                                                                                                                       [ ok ]
>>> Source prepared.
>>> Configuring source in /var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/work/libmemcached-1.0.17 ...
 * ERROR: dev-libs/libmemcached-1.0.17-r1::gentoo failed (configure phase):
 *   USE Flag 'sasl' not in IUSE for dev-libs/libmemcached-1.0.17-r1
 * 
 * Call stack:
 *          ebuild.sh, line   93:  Called src_configure
 *        environment, line 1858:  Called use_enable 'sasl' 'sasl'
 *   phase-helpers.sh, line  254:  Called use 'sasl'
 *   phase-helpers.sh, line  200:  Called die
 * The specific snippet of code:
 *   				die "USE Flag '${u}' not in IUSE for ${CATEGORY}/${PF}"
 * 
 * If you need support, post the output of `emerge --info '=dev-libs/libmemcached-1.0.17-r1::gentoo'`,
 * the complete build log and the output of `emerge -pqv '=dev-libs/libmemcached-1.0.17-r1::gentoo'`.
 * The complete build log is located at '/var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/temp/environment'.
 * Working directory: '/var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/work/libmemcached-1.0.17'
 * S: '/var/tmp/portage/dev-libs/libmemcached-1.0.17-r1/work/libmemcached-1.0.17'