dylan-environment and dylan-compiler are not terminal-child-friendly

[promovicz]

While creating Docker images I noticed that calling an external shell with "os /bin/sh" does not seem to work correctly terminal-wise. Output from the child shell is garbled and it doesn't display a prompt. It seems like dylan-environment puts the terminal in raw mode without resetting it before starting the child, or something similar.

[housel]

The os command redirects the output of the child process to a pipe so that it can use the environment's regular message output. This allows the output to go to the right place if you're using the Tools > Command Line... window in the GUI, but it's unnecessary if you're just using the CLI environment.