Thanks to @jcumming for notifying me about this in #nixos:
03:47 < jack_c> aszlig: chromium builds with -Werror by default.
03:47 < jack_c> Putting: werror = "";
03:48 < jack_c> into gypFlags fixes that..
...
03:52 < jack_c> aszlig: agree -Werror is a good linting tool, but it should
probably disabled for distribution.
So, I guess it makes sense in our case, especially because different GCC
versions will issue different warnings.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>