ref: 95b9b8863d747698cfb27d92f6160a588703acf3
parent: 76ed42e31ff3297f1ca9b144ccc9466b0074f92b
author: Alex Musolino <alex@musolino.id.au>
date: Tue Jan 5 17:36:03 EST 2021
qr: fix exit status Call exits(0) instead of returning from main. Also call sysfatal if writing of image data fails. Previously, qr(1) would exit with default non-nil status "main" unconditionally as a result of returning from main.