- Catch SIGHUP to perform cleanup before exiting.
- Exit if getch() returns with an error other than EINTR. Otherwise
systat(1) may get stuck in an infinite loop if it doesn't receive
SIGHUP when terminal closes.
- Remove attempt to clear stdio error indicators. getch() doesn't use
stdio, making it useless.
- Remove unneeded masking of getch() return value.
PR: bin/107171
Approved by: trasz (mentor)
1df0fb5d0b