Bouncy Castle in Nixpkgs

[msgilligan]

I would like to submit a PR to add Bouncy Castle to Nixpkgs. I would prefer that it be a "source provenance" package (i.e. built in a Nix sandbox using Gradle rather than just pulling binaries from Maven Central and verifying hashes.)

It looks like someone started a Nixpkgs PR for Bouncy Castle in 2015 using Ant (which was probably the official build tool for Bouncy Castle at the time.)

If anyone has done any work on this, has any ideas, or wants to help, please comment here!

I think my first step will be to create a temporary repo with a Nix flake that focuses on building bcprov-jdk18on-1.84.jar with the openjdk21 and gradle_9 packages.