^G detaches text-mode emacs from terminal

When started in a terminal using something like `flatpak run org.gnu.emacs -nw`, inserting a ^G character (ctrl-G) seems to cause the emacs process to lose control of the terminal. Typically then a bash prompt gets drawn on top of the Emacs process and it starts receiving all the input written on the terminal.

This seems to be somehow related to how the input is delivered to Emacs. Evaluating `(keyboard-quit)` by some other means than pressing ctrl-G behaves as expected.

Currently this makes the flatpak difficult to use in text mode.