mozilla@gentoo.org Gentoo Mozilla Team Disable official Thunderbird branding (icons, name) which are not binary-redistributable according to upstream. Use Clang compiler instead of GCC Enable encryption support with enigmail Enable Mozilla's DOM inspector Enable app-global calendar support (note 38.0 and above bundles calendar support when this flag is off) Build with user-specified compiler optimizations (-Os, -O0, -O1, -O2, -O3) from CFLAGS (unsupported) Use the cairo-gtk2 rendering engine instead of the default cairo-gtk3 Enable support for using rust compiler (experimental) Use the system-wide x11-libs/cairo instead of bundled. Use the system-wide media-libs/harfbuzz and media-gfx/graphite2 instead of bundled. Use the system-wide dev-libs/icu instead of bundled. Use the system-wide media-libs/libjpeg-turbo instead of bundled. Use the system-wide dev-libs/libevent instead of bundled. Use the system-wide media-libs/libvpx instead of bundled. Use the system-wide dev-db/sqlite installation with secure-delete enabled Remove the software development kit and headers