...hopefully.
This avoids distorted images, and also preserves a correct ar, even on crop 1:1.

refs #6080
(cherry picked from commit 4a1c818c067a5481f06bcbcf0d7a5d7b56db1a8b)

Conflicts:

	modules/video_output/macosx.m
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>