Steam runtime not starting after update on arch linux

[Lunae Bellator (@Arch Linux)]

Heyho,
I have a huge problem: The steam runtime on my arch linux system won't start. I did an update yesterday. Before that, steam and all my steam games ran well! Now the following happpens: If I put the command "steam" in my console, I get the following output:
Running Steam on arch rolling 64-bit
STEAM_RUNTIME is enabled automatically
right after that, the program just stops and I am back on my standard command line.

When searching for the problem on the Internet, I found a lot of people get libgl errors but I don't get any error messages or anything. I also have nvidia-utils and lib32-nvidia-utils installed. Also, this is happening no matter if I type "steam", "steam-runtime" or "steam-native" in my console, the only exception is that in the case of steam-native I get "STEAM_RUNTIME is disabled by the user."

I also installed gdb and tried "DEBUGGER=gdb steam" then I typed "run" and then "backtrace" but I just got "No stack" back. So I really don't have a clue why the runtime doesn't start. The same also happens if I just click the starter icons instead of starting steam from console: the loading icon shortly appears but than vanishes instantaneously.

Any ideas?

PS: I also tried all the stuff described in the arch wiki at "runtime issues"

[DirtyFishy]

http://steamcommunity.com/app/221410/discussions/