snowball: Set TARGET_EXTRA_CFLAGS

Setting TARGET_GLOBAL_CFLAGS here didn't accomplish anything
because TARGET_GLOBAL_CFLAGS was reset later by config.mk.
TARGET_EXTRA_CFLAGS (introduced in commit
959a2d9f816f14b05e8b9896110b59c389228b5c) is added to
TARGET_GLOBAL_CFLAGS at the right time, actually making sure
the flags are used.

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
1 file changed