the terminal driver's treatment of the control-D (EOF) and escape
keys on Unix-like OSs. But escape has no special meaning, and treating
control-D as a line terminator was probably to prevent unexpected
session exit when connected through a modem without error-correction.
Removing the function allows "ngspice netlist &" to work correctly.
The function was called during initialisation, which caused an endless
loop of job-control stops when ngspice was started as a background process.