gentoo-overlay/mail-client/thunderbird/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
<herd>mozilla</herd>
<use>
	<flag name="bindist">Disable official Thunderbird branding (icons, name) which 
		are not binary-redistributable according to upstream.</flag>
	<flag name='crypt'> Enable encryption support with enigmail</flag>
	<flag name='mozdom'>Enable Mozilla's DOM inspector</flag>
	<flag name='lightning'>Enable calendar support</flag>
	<flag name='custom-optimization'>Fine-tune custom compiler optimizations
		(-Os, -O0, -O1, -O2, -O3)</flag>
	<flag name="system-cairo">Use the system-wide <pkg>x11-libs/cairo</pkg>
		instead of bundled.</flag>
	<flag name="system-icu">Use the system-wide <pkg>dev-libs/icu</pkg>
		instead of bundled.</flag>
	<flag name="system-jpeg">Use the system-wide <pkg>media-libs/libjpeg-turbo</pkg>
		instead of bundled.</flag>
	<flag name="system-libvpx">Use the system-wide <pkg>media-libs/libvpx</pkg>
		instead of bundled.</flag>
	<flag name="system-sqlite">Use the system-wide <pkg>dev-db/sqlite</pkg>
		installation with secure-delete enabled</flag>
	<flag name="minimal">Remove the software development kit and headers</flag>
</use>
</pkgmetadata>