gentoo-overlay/dev-libs/log4cxx/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
<maintainer type="project">
  <email>cpp@gentoo.org</email>
  <name>Gentoo C++ Project</name>
</maintainer>
<use>
  <flag name="smtp" restrict="&lt;dev-libs/log4cxx-0.10">Offer SMTP support via
    <pkg>net-libs/libsmtp</pkg></flag>
  <flag name="smtp" restrict="&gt;=dev-libs/log4cxx-0.10">Offer SMTP support via
    <pkg>net-libs/libesmtp</pkg></flag>
</use>
</pkgmetadata>