gentoo-overlay/sci-misc/boinc/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <herd>sci</herd>
  <longdescription lang="en">
  BOINC (Berkeley Open Infrastructure for Network Computing) is a software
  platform for distributed computing using volunteered computer resources.
</longdescription>
  <use>
    <flag name="cuda">
  Use nvidia cuda toolkit for speeding up computations.
  NOTE: works only for subset of nvidia graphic cards so make sure your card
  is supported before opening bug about it.
  </flag>
  </use>
</pkgmetadata>