Calculating dependencies  .. ... done!

>>> Verifying ebuild manifests

>>> Emerging (1 of 4) www-servers/apache-2.4.16::gentoo
 * httpd-2.4.16.tar.bz2 SHA256 SHA512 WHIRLPOOL size ;-) ...             [ ok ]
 * gentoo-apache-2.4.10-r1-20140731.tar.bz2 SHA256 SHA512 WHIRLPOOL size ;-) ...       [ ok ]
 * 
 * Selected MPM: prefork
 * 
 * You have selected a non-threaded MPM but USE=threads is enabled
 * ERROR: www-servers/apache-2.4.16::gentoo failed (setup phase):
 *   invalid use flag combination
 * 
 * Call stack:
 *              ebuild.sh, line  93:  Called pkg_setup
 *   apache-2.4.16.ebuild, line 137:  Called apache-2_pkg_setup
 *        apache-2.eclass, line 392:  Called setup_mpm
 *        apache-2.eclass, line 167:  Called die
 * The specific snippet of code:
 *   		die "invalid use flag combination"
 * 
 * If you need support, post the output of `emerge --info '=www-servers/apache-2.4.16::gentoo'`,
 * the complete build log and the output of `emerge -pqv '=www-servers/apache-2.4.16::gentoo'`.
 * The complete build log is located at '/var/tmp/portage/www-servers/apache-2.4.16/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/www-servers/apache-2.4.16/temp/die.env'.
 * Working directory: '/usr/lib64/python3.3/site-packages'
 * S: '/var/tmp/portage/www-servers/apache-2.4.16/work/httpd-2.4.16'

>>> Failed to emerge www-servers/apache-2.4.16, Log file:

>>>  '/var/tmp/portage/www-servers/apache-2.4.16/temp/build.log'
 * Messages for package www-servers/apache-2.4.16:
 * 
 * Selected MPM: prefork
 * 
 * You have selected a non-threaded MPM but USE=threads is enabled
 * ERROR: www-servers/apache-2.4.16::gentoo failed (setup phase):
 *   invalid use flag combination
 * 
 * Call stack:
 *              ebuild.sh, line  93:  Called pkg_setup
 *   apache-2.4.16.ebuild, line 137:  Called apache-2_pkg_setup
 *        apache-2.eclass, line 392:  Called setup_mpm
 *        apache-2.eclass, line 167:  Called die
 * The specific snippet of code:
 *   		die "invalid use flag combination"
 * 
 * If you need support, post the output of `emerge --info '=www-servers/apache-2.4.16::gentoo'`,
 * the complete build log and the output of `emerge -pqv '=www-servers/apache-2.4.16::gentoo'`.
 * The complete build log is located at '/var/tmp/portage/www-servers/apache-2.4.16/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/www-servers/apache-2.4.16/temp/die.env'.
 * Working directory: '/usr/lib64/python3.3/site-packages'
 * S: '/var/tmp/portage/www-servers/apache-2.4.16/work/httpd-2.4.16'