Packaging Telegram Messenger

[dpg]

Hello! 
I'm currently working on getting the Telegram instant messenger packaged and
would be very pleased with any assistance fellow hackers can offer. Currently I
have a patch filed [1] for one dependency, however there are three other in
various states of development in my guix repo [2] and at least one more
completely unpackaged (libappindicator[-gtk3]). Currently, I've been basing my
work off the already, helpfully, packaged version in nixos [3]. Any help that
people can provide is much appreciated. Submitting a PR or emailing me a patch
would preferred - feel free to hit me up in IRC aswell.
Thanks!
[1] http://lists.gnu.org/archive/html/guix-patches/2018-02/msg00021.html
[2] https://notabug.org/doubleplusgood23/guix
[3] https://github.com/NixOS/nixpkgs/blob/c1d9aff56e0ae52ee4705440fe09291a51e919
77/pkgs/applications/networking/instant-
messengers/telegram/tdesktop/default.nix#L104