ref #4181

to avoid conflict with qt4

The ownCloud Desktop Client is a tool to synchronize files from ownCloud Server with your computer

Fixes #4189

Qt API to store passwords and other secret data securely

ref #4017

- use libedit instead of gnu readline.
- avoid pull in unnecessary deps for -dev (ref #4109)

The glx tls causes segfault with musl libc:
https://bugs.freedesktop.org/show_bug.cgi?id=35268

The glx tls is there for performance reasons that only affects glibc. On
musl libc it should not make any difference so we simply disable it.