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

Calculating dependencies  ... done!
[ebuild  N    ~] net-misc/mikutter-0.1.0.723  USE="libnotify -sound -test" RUBY_TARGETS="-ruby19" 0 kB

Total: 1 package (1 new), Size of downloads: 0 kB

Would you like to merge these packages? [Yes/No] >>> Verifying ebuild manifests
>>> Jobs: 0 of 1 complete, 1 running                Load avg: 0.05, 0.09, 0.16
>>> Emerging (1 of 1) net-misc/mikutter-0.1.0.723
>>> Jobs: 0 of 1 complete, 1 running                Load avg: 0.05, 0.09, 0.16
>>> Failed to emerge net-misc/mikutter-0.1.0.723, Log file:
>>> Jobs: 0 of 1 complete, 1 running                Load avg: 0.12, 0.11, 0.16
>>>  '/var/tmp/portage/net-misc/mikutter-0.1.0.723/temp/build.log'
>>> Jobs: 0 of 1 complete, 1 running                Load avg: 0.12, 0.11, 0.16
>>> Jobs: 0 of 1 complete, 1 running, 1 failed      Load avg: 0.12, 0.11, 0.16
>>> Jobs: 0 of 1 complete, 1 failed                 Load avg: 0.12, 0.11, 0.16

 * Package:    net-misc/mikutter-0.1.0.723
 * Repository: gentoo
 * Maintainer: naota@gentoo.org
 * USE:        amd64 consolekit elibc_glibc kernel_linux libnotify multilib policykit userland_GNU
 * FEATURES:   ccache sandbox
 * You need to select at least one compatible Ruby installation target via RUBY_TARGETS in make.conf.
 * Compatible targets for this package are: ruby19
 *
 * See http://www.gentoo.org/proj/en/prog_lang/ruby/index.xml#doc_chap3 for more information.
 *
 * ERROR: net-misc/mikutter-0.1.0.723 failed (setup phase):
 *   No compatible Ruby target selected.
 *
 * Call stack:
 *        ebuild.sh, line  85:  Called pkg_setup
 *        ebuild.sh, line 315:  Called ruby-ng_pkg_setup
 *   ruby-ng.eclass, line 404:  Called _ruby_each_implementation
 *   ruby-ng.eclass, line 393:  Called die
 * The specific snippet of code:
 *   		die "No compatible Ruby target selected."
 *
 * If you need support, post the output of 'emerge --info =net-misc/mikutter-0.1.0.723',
 * the complete build log and the output of 'emerge -pqv =net-misc/mikutter-0.1.0.723'.
!!! When you file a bug report, please include the following information:
GENTOO_VM=  CLASSPATH="" JAVA_HOME=""
JAVACFLAGS="" COMPILER=""
and of course, the output of emerge --info
 * The complete build log is located at '/var/tmp/portage/net-misc/mikutter-0.1.0.723/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/net-misc/mikutter-0.1.0.723/temp/die.env'.
 * S: '/var/tmp/portage/net-misc/mikutter-0.1.0.723/work/mikutter'

 * Messages for package net-misc/mikutter-0.1.0.723:

 * You need to select at least one compatible Ruby installation target via RUBY_TARGETS in make.conf.
 * Compatible targets for this package are: ruby19
 *
 * See http://www.gentoo.org/proj/en/prog_lang/ruby/index.xml#doc_chap3 for more information.
 *
 * ERROR: net-misc/mikutter-0.1.0.723 failed (setup phase):
 *   No compatible Ruby target selected.
 *
 * Call stack:
 *        ebuild.sh, line  85:  Called pkg_setup
 *        ebuild.sh, line 315:  Called ruby-ng_pkg_setup
 *   ruby-ng.eclass, line 404:  Called _ruby_each_implementation
 *   ruby-ng.eclass, line 393:  Called die
 * The specific snippet of code:
 *   		die "No compatible Ruby target selected."
 *
 * If you need support, post the output of 'emerge --info =net-misc/mikutter-0.1.0.723',
 * the complete build log and the output of 'emerge -pqv =net-misc/mikutter-0.1.0.723'.
 * The complete build log is located at '/var/tmp/portage/net-misc/mikutter-0.1.0.723/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/net-misc/mikutter-0.1.0.723/temp/die.env'.
 * S: '/var/tmp/portage/net-misc/mikutter-0.1.0.723/work/mikutter'
 *
 * The following package has failed to build or install:
 *
 *  (net-misc/mikutter-0.1.0.723::gentoo, ebuild scheduled for merge), Log file:
 *   '/var/tmp/portage/net-misc/mikutter-0.1.0.723/temp/build.log'
 *