Below is the full patch for convenience.  I plan to commit it on Friday
or Saturday, after a cosmetic check.  Especially the description could
use some work, and the grouping of "configure flags".

One final note for future contributors is that Gentoo[2] is kind-of
upstream for Chromium, as ChromiumOS is based on Portage and I've seen
several Gentoo developers on the Chromium bug tracker.  They often have
early compatibility patches (e.g. when it invariably breaks with GCC).

[0] https://anonscm.debian.org/cgit/pkg-chromium/pkg-chromium.git/commit/?id=794aa1820460727711e534ea1042db7eebc1601d
[1] https://git.archlinux.org/svntogit/packages.git/commit/trunk?h=packages/chromium&id=6ebdd8085de0b7c8bbc66e47b937271ab4a85fbd
[2] https://gitweb.gentoo.org/repo/gentoo.git/tree/www-client/chromium