gentoo-overlay/gnome-base/gnome-common/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="autoconf-archive">Pull in <pkg>sys-devel/autoconf-archive</pkg> for ax_*.m4 files
		instead of installing them from the gnome-common tarball</flag>
</use>
</pkgmetadata>