This file has been exported since our minimum required version (0.7.0),
but it wasn't documented. Instead it was transitively included by
<jxl/decode.h> (but not jxl/encode.h), which ffmpeg relied on.
libjxl broke its API in libjxl/libjxl@66b9592393 by removing
the transitive include of version.h, and they do not plan on adding
it back. Instead they are choosing to leave the API backwards-
incompatible with downstream callers written for some fairly recent
versions of their API.
As a result, we include <jxl/version.h> to continue to build against
more recent versions of libjxl. The version macros removed are also
present in that file, so we no longer need to redefine them.
Signed-off-by: Leo Izen <leo.izen@gmail.com>
Since many distributions ship libjxl 0.7.0 still, we'd still prefer to
compile against that, but don't want to lose the features that require
libjxl 0.8.0 or greater. For this reason I've added preprocessor #ifdef
guards around the features that aren't necessarily in libjxl 0.7.0.
Signed-off-by: Leo Izen <leo.izen@gmail.com>
