The flag is not present in 3.6.
Also add compatibility patches for 3.3.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@33971 3c298f89-4303-0410-b956-a3cf2f4a3e73