gentoo-overlay/app-emacs/company-mode/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
<herd>emacs</herd>
<use>
  <flag name='ropemacs'>Install backend for <pkg>dev-python/ropemacs</pkg>
  </flag>
  <flag name='semantic'>Install backend for semantic
    (<pkg>app-emacs/cedet</pkg>)</flag>
</use>
</pkgmetadata>