Comment 73 for bug 1189850

(In reply to comment #53)
> Reading
> firefox-19.0.2.ebuild?view=markup it seems that the use of system-cairo has
> been dropped. Which is a shame.

Well, you've seen the patches applied on top of firefox and support for system cairo is there. Out of curiosity I've run some initial steps of firefox build and here's a bit filtered result:

grep cairo /var/tmp/portage/www-client/firefox-19.0.2/temp/build.log
 * 6009_fix_system_cairo_support.patch ...
    --enable-system-cairo system_libs
    --enable-default-toolkit=cairo-gtk2 default
checking for cairo >= 1.10... yes
checking CAIRO_CFLAGS... -I/usr/include/cairo -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libdrm -I/usr/include/libpng15
checking CAIRO_LIBS... -lcairo
checking for cairo-tee >= 1.10... yes
checking CAIRO_TEE_CFLAGS... -I/usr/include/cairo -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libdrm -I/usr/include/libpng15
checking CAIRO_TEE_LIBS... -lcairo
checking for cairo-xlib-xrender >= 1.10... yes
checking CAIRO_XRENDER_CFLAGS... -I/usr/include/cairo -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libdrm -I/usr/include/libpng15
checking CAIRO_XRENDER_LIBS... -lcairo -lXrender -lX11

and this is output from already built firefox I am running now:

ldd /usr/lib/firefox/ | grep cairo => /usr/lib64/ (0x00007f205d497000) => /usr/lib64/ (0x00007f2059cc2000)

So, system-wide cairo enabled at build time and it is really there as shown by ldd.