The new GLib deprecated some threading API, but gst-openmax wasn't detecting
release vs development at all so assuming development, and thus building with
-Werror. Set the variable that the configure script is assuming to exist, so
that -Werror isn't used.
(From OE-Core rev: 26bf8f6a047ccc0f73eaa40093afddabfce8ea1b)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>