gentoo-overlay/www-client/firefox/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 Firefox branding (icons, name) which 
		are not binary-redistributable according to upstream.</flag>
	<flag name="custom-optimization">Fine-tune custom compiler
		optimizations, setting this is not recommended.</flag>
	<flag name="crashreporter">Enable crashreporter for mozilla upstream, debugging
		symbols are not required for reporting crashes.</flag>
	<flag name="ipc">Use inter-process communication between tabs and plugins.
		Allows for greater stability in case of plugin crashes</flag>
	<flag name="minimal"> Prevent sdk and headers from being installed</flag>
	<flag name="pgo">Add support for profile-guided optimization using gcc-4.5,
		for faster binaries. This option will double the compile time.</flag>
	<flag name="system-sqlite">Use the system-wide <pkg>dev-db/sqlite</pkg>
		installation with secure-delete enabled</flag>
	<flag name="webm">Use system <pkg>media-libs/libvpx</pkg> for HTML5 WebM
		video support.</flag>
</use>
</pkgmetadata>