#559 crash when DOS pgm access serial port

[Michael Powell]

This is on an UP board with dosemu 1.4.0.7+20130105+b028d3f-2_b1 installed, running under ubilinux which is a derivative of debian 9.0 (and uses current debian pkg sources). I am using /dev/ttyUSB0 with a ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port USB-to-Serial adaptor and a USR modem attached to the other end. I am able to access the device (under the same user ID) with minicom, and have confirmed user is in dialout group, which is group that owns device. boot.log error message sent me here. Thanks.