Ignore conversions to NULL in gcc too.

Do something similar to r129758 and disable conversion to NULL warnings in
gcc >= 4.5.0 as well. The -Wno-conversion-null option was added in that
version, and not passing it makes the build fail when -Werror is activated
(the default).

R=hbono@chromium.org, thakis@chromium.org
TEST=Build with gcc >= 4.5.0 and -Werror.
Review URL: https://codereview.chromium.org/14195026/

Patch from Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>!

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/hunspell@195440 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
1 file changed