Create byzantium branch

Chatty requires olm for handling matrix encryption, and through libpurple lurch plugin chatty indirectly depends on libaxc. Both libaxc and olm declares some functions having same name, and this results in conflict. That is, when lurch plugin calls a libaxc function, the function libolm is executed instead.

This patch renames those symbols to avoid the conflict

Fixes Librem5/chatty#450

The build requires dpkg 1.20.1 and pureOS has only 1.19.7.

This one is for byzantium so that I can tag new beta release for chatty

/cc @guido.gunther