Error messages indisinguishable from app or firejail

[Bill Yikes]

It's really annoying that firejail simply tags error msgs with "Error:", and not "Firejail error:".

How are users supposed to know if the error is reported by Firejail, or the app that firejail is running?

This code is littered with anonymous error messages that makes troubleshooting difficult:

https://github.com/netblue30/firejail/blob/master/src/firejail/main.c

E.g.

fprintf(stderr, "Error: too many environment variables\n");