GNU `screen -dmS` causes commandline to break and CPU spin

1. Run commandline_test as `screen -dmS test commandline_test`
2. Observe 100% CPU spin
3. Attach via `screen -r test` and observe completely bugged input

- [ ] `screen -dmS` should work as expected
- [ ] there should be no CPU spin possible

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Notes

- it may be that isatty() changes after initialization(?)