* Update jdk from v8 to v11 to keep it building.
* There are no jreMAJOR_headless versions above MAJOR=8 and jre_minimal
doesn't work[1], so switch to jre_headless (currently v21 on
nixpkgs-unstable) to keep it running. The newer jre causes a big
package closure size difference: 153 MiB -> 627 MiB.
* Upstream changed the way `git describe` info gets built into the
artifacts, so add a postPatch snippet to handle that.
(Fixes `Error: inStream parameter is null` issue that happens
otherwise.)
Upstream asked for a suffix to the version string to differentiate
from official builds; use "-nixpkgs" for that.
[1] $ gp -i
Error: Unable to initialize main class pro.javacard.gptool.GPTool
Caused by: java.lang.NoClassDefFoundError: javax/smartcardio/CardException
3ca92ac225