server01 ~ # emerge -v dev-ruby/rdoc

 * IMPORTANT: 2 config files in '/etc/portage' need updating.
 * See the CONFIGURATION FILES and CONFIGURATION FILES UPDATE TOOLS
 * sections of the emerge man page to learn how to update config files.

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

Calculating dependencies... done!
[ebuild   R   ~] dev-ruby/rdoc-6.0.0::gentoo  USE="-doc {-test}" RUBY_TARGETS="ruby22 ruby23 ruby24*" 0 KiB

Total: 1 package (1 reinstall), Size of downloads: 0 KiB


>>> Verifying ebuild manifests

>>> Emerging (1 of 1) dev-ruby/rdoc-6.0.0::gentoo
 * rdoc-6.0.0.tar.gz BLAKE2B SHA512 size ;-) ...                                                                                                                                                                                      [ ok ]
>>> Unpacking source...
 * Running unpack phase for all ...
>>> Unpacking rdoc-6.0.0.tar.gz to /tmp/portage/dev-ruby/rdoc-6.0.0/work/all
>>> Source unpacked in /tmp/portage/dev-ruby/rdoc-6.0.0/work
>>> Preparing source in /tmp/portage/dev-ruby/rdoc-6.0.0/work ...
 * Running prepare phase for all ...
 * Running source copy phase for ruby22 ...
 * Running source copy phase for ruby23 ...
 * Running source copy phase for ruby24 ...
>>> Source prepared.
>>> Configuring source in /tmp/portage/dev-ruby/rdoc-6.0.0/work ...
>>> Source configured.
>>> Compiling source in /tmp/portage/dev-ruby/rdoc-6.0.0/work ...
 * Running compile phase for ruby22 ...
Generating lib/rdoc/rd/block_parser.rb...
/usr/bin/ruby22 /usr/lib64/ruby/gems/2.2.0/gems/racc-1.4.14/bin/racc -l -o lib/rdoc/rd/block_parser.rb lib/rdoc/rd/block_parser.ry
Generating lib/rdoc/rd/inline_parser.rb...
/usr/bin/ruby22 /usr/lib64/ruby/gems/2.2.0/gems/racc-1.4.14/bin/racc -l -o lib/rdoc/rd/inline_parser.rb lib/rdoc/rd/inline_parser.ry
Generating lib/rdoc/markdown.rb...
/usr/bin/ruby22 /usr/lib64/ruby/gems/2.2.0/gems/kpeg-1.1.0/bin/kpeg -fsv -o lib/rdoc/markdown.rb lib/rdoc/markdown.kpeg
Wrote RDoc::Markdown to lib/rdoc/markdown.rb
Generating lib/rdoc/markdown/literals.rb...
/usr/bin/ruby22 /usr/lib64/ruby/gems/2.2.0/gems/kpeg-1.1.0/bin/kpeg -fsv -o lib/rdoc/markdown/literals.rb lib/rdoc/markdown/literals.kpeg
Wrote RDoc::Markdown::Literals to lib/rdoc/markdown/literals.rb
 * Running compile phase for ruby23 ...
Generating lib/rdoc/rd/block_parser.rb...
/usr/bin/ruby23 /usr/lib64/ruby/gems/2.3.0/gems/racc-1.4.14/bin/racc -l -o lib/rdoc/rd/block_parser.rb lib/rdoc/rd/block_parser.ry
Generating lib/rdoc/rd/inline_parser.rb...
/usr/bin/ruby23 /usr/lib64/ruby/gems/2.3.0/gems/racc-1.4.14/bin/racc -l -o lib/rdoc/rd/inline_parser.rb lib/rdoc/rd/inline_parser.ry
Generating lib/rdoc/markdown.rb...
/usr/bin/ruby23 /usr/lib64/ruby/gems/2.3.0/gems/kpeg-1.1.0/bin/kpeg -fsv -o lib/rdoc/markdown.rb lib/rdoc/markdown.kpeg
Wrote RDoc::Markdown to lib/rdoc/markdown.rb
Generating lib/rdoc/markdown/literals.rb...
/usr/bin/ruby23 /usr/lib64/ruby/gems/2.3.0/gems/kpeg-1.1.0/bin/kpeg -fsv -o lib/rdoc/markdown/literals.rb lib/rdoc/markdown/literals.kpeg
Wrote RDoc::Markdown::Literals to lib/rdoc/markdown/literals.rb
 * Running compile phase for ruby24 ...
/usr/lib64/ruby/site_ruby/2.4.0/rubygems.rb:280:in `find_spec_for_exe': can't find gem rake ([">= 0.a"]) with executable rake (Gem::GemNotFoundException)
        from /usr/lib64/ruby/site_ruby/2.4.0/rubygems.rb:299:in `activate_bin_path'
        from /usr/local/bin/rake:23:in `<main>'
 * ERROR: dev-ruby/rdoc-6.0.0::gentoo failed (compile phase):
 *   (no error message)
 *
 * Call stack:
 *     ebuild.sh, line  124:  Called src_compile
 *   environment, line 4437:  Called ruby-ng_src_compile
 *   environment, line 4129:  Called _ruby_each_implementation 'each_ruby_compile'
 *   environment, line  472:  Called _ruby_invoke_environment 'ruby24' 'each_ruby_compile'
 *   environment, line  593:  Called each_ruby_compile
 *   environment, line  909:  Called die
 * The specific snippet of code:
 *       ${RUBY} -S rake generate || die
 *
 * If you need support, post the output of `emerge --info '=dev-ruby/rdoc-6.0.0::gentoo'`,
 * the complete build log and the output of `emerge -pqv '=dev-ruby/rdoc-6.0.0::gentoo'`.
!!! When you file a bug report, please include the following information:
GENTOO_VM=  CLASSPATH="" JAVA_HOME="/etc/java-config-2/current-system-vm"
JAVACFLAGS="" COMPILER=""
and of course, the output of emerge --info =rdoc-6.0.0
 * The complete build log is located at '/log/portage/dev-ruby:rdoc-6.0.0:20171218-165943.log'.
 * For convenience, a symlink to the build log is located at '/tmp/portage/dev-ruby/rdoc-6.0.0/temp/build.log'.
 * The ebuild environment file is located at '/tmp/portage/dev-ruby/rdoc-6.0.0/temp/environment'.
 * Working directory: '/tmp/portage/dev-ruby/rdoc-6.0.0/work/ruby24/rdoc-6.0.0'
 * S: '/tmp/portage/dev-ruby/rdoc-6.0.0/work/ruby24/rdoc-6.0.0'

>>> Failed to emerge dev-ruby/rdoc-6.0.0, Log file:

>>>  '/log/portage/dev-ruby:rdoc-6.0.0:20171218-165943.log'
 *
 * The following package has failed to build, install, or execute postinst:
 *
 *  (dev-ruby/rdoc-6.0.0:0/0::gentoo, ebuild scheduled for merge), Log file:
 *   '/log/portage/dev-ruby:rdoc-6.0.0:20171218-165943.log'
 *
server01 ~ #