On the Windows GUI (nethackw.exe), while running the fuzzer,
if the NetHack window gets minimized, or someone minimizes all
desktop windows, the NetHack window stops responding and won't
even repaint itself. The NetHack process continues to use the
CPU.
A break in the debugger shows that it is caught in a do loop.
I didn't delve into the issue of why minimizing the window
triggers a condition that leads to the endless loop. This
just adds a kludge to exit the loop while fuzzing.
87af3a8cac