gentoo-overlay/gnome-extra/evolution-data-server/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
	<maintainer type="project">
		<email>gnome@gentoo.org</email>
		<name>Gentoo GNOME Desktop</name>
	</maintainer>
	<use>
		<flag name="berkdb"><pkg>sys-libs/db</pkg> support needed to migrate old (pre-3.13 evolution versions) addressbook data</flag>
		<flag name="gnome-online-accounts">Enable <pkg>net-libs/gnome-online-accounts</pkg> based Google authentication support</flag>
		<flag name="oauth">Enable internal OAuth2 authentication support for Google and Outlook.com.
			If gnome-online-accounts is enabled and used, this is not necessary,
			but both can be supported at the same time with different setup at runtime</flag>
		<flag name="weather">Enable optional weather calendar support</flag>
	</use>
</pkgmetadata>