fix: Better compatible with jsonrpc

[jcs090218]

For #258.

[emil-vdw]

Have you tested on old and new version of jsonrpc?

[jcs090218]

Yes, it both works for me. :)

[emil-vdw]

Don't you think that it would be better for this "old" jsonrpc version to be hardcoded? It's not really like it can change and we should only use the old parameter when it is older than that specific version not when it is older than the version we currently rely upon. I.e. at some point we may update the version of jsonrpc we depend on but the logic would break.

[jcs090218]

I'm not sure what you mean. Can you elaborate? 🤔

[emil-vdw]

Nevermind, I was confused there for a second. LGTM. 👍

[jkl1337]

This is completely broken. Package-Requires is not at a sufficient version (28.1). Compilation breaks due to missing (require 'package) -- (suggest using package-lint to prevent these issues). Furthermore, package-get-descriptor is only going to work if the descriptor is loaded first, and just requiring 'jsonrpc doesn't do that. As it is this breaks emacs startup.

I haven't dove into this issue, but this approach overall seems suspect. Can this not be done with feature detection?