In addition to updating for the latest release on GitHub, this adds
support for three new *features*:
* **jpeg** this adds JPEG support for Linux (Windows already supports
JPEG via the built-in WIC codec)
* **png** this adds PNG support for Linux (Windows already supports PNG
via the built-in WIC codec)
* **xbox** this builds the library for PC but with Xbox extensions for
development. Requires the Microsoft GDKX. By default it targets Xbox
Series X|S. To target Xbox One instead, you can use a triplet variable
as described in the update usage.