gentoo-overlay/dev-libs/ace/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
<!-- maintainer-needed -->
<use>
  <flag name="ciao">Include Component Intergraced Ace ORB into the build of
    ace</flag>
  <flag name="tao">Include the ACE ORB (CORBA stuff) (called tao) into the
    build of ace</flag>
</use>
</pkgmetadata>