Since we started depending on GLib 2.44, we can be sure this macro is
defined (it will be a no-op on compilers that don't support it). For
plugins we should just start using `G_DECLARE_FINAL_TYPE` which means we
no longer need the macro there, but for most types in base/gst-libs we
don't want to break ABI, which means it's better to just keep it like it
is (and use the `#ifdef` instead).
We need different export decorators for the different libs.
For now no actual change though, just rename before the release,
and add prelude headers to define the new decorator to GST_EXPORT.
Expose the gst_video_info_align function that adds padding and does stride
alignment on a GstVideoInfo. Move this previously private function to
video-info.co
Move the definition of the alignment structure to video.h where it can be picked
up by both the bufferpool and the video-info.
We require the videometa activated before we can implement the alignment of
buffers. Users of the bufferpool should do this manually based on the results of
the allocation query.
