This exposes some required functionality like _aligned_malloc() in the
MinGW system headers, thus obviating the need for the memalign hack.

The code currently reads the coded dimensions from the extradata, but
expects the display dimensions to be set by the caller, and does not
check that they are compatible (i.e. that the displayed size is smaller
than the coded size).

Make sure that when the display dimensions are set, they are also valid.
Fixes possible invalid memory access.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

Fixes possible invalid reads.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

Fixes possible invalid reads.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

Fixes possible invalid reads.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

It is passed to the get_bits API, which requires buffers to be padded.

Fixes possible invalid reads.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

Fixes possible invalid reads in corrupted files.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

height - me_y is the line from which we read, so it must be strictly
smaller than the frame height. Fixes possible invalid reads in corrupted
files.

Also, use a proper context for logging the error.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

If we encounter an END element before anything is decoded, we would
return success even though the output frame has not been allocated,
which is invalid.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

Fixes possible invalid writes with corrupted files.

CC: libav-stable@libav.org
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind

This gem has been disabled since 2001.

The lowest supported VAAPI version is 0.34 (checked at configure
time), so this test is no longer needed.

If no string argument is supplied when av_hwdevice_ctx_create() is
called to create a VAAPI device, we currently only try the default
X11 display (that is, $DISPLAY) to find a device, and will therefore
fail in the absence of an X server to connect to.  Change the logic
to also look for a device via the first DRM render node (that is,
"/dev/dri/renderD128"), which is probably the right thing to use in
most simple configurations which only have one DRM device.