buildroot/board/qemu/x86/post-build.sh

#!/bin/sh

set -u
set -e

# Add a console on tty1
if [ -e "${TARGET_DIR}/etc/inittab" ]; then
    grep -qE '^tty1::' "${TARGET_DIR}/etc/inittab" || \
	sed -i '/GENERIC_SERIAL/a\
tty1::respawn:/sbin/getty -L  tty1 0 vt100 # QEMU graphical window' "${TARGET_DIR}/etc/inittab"
fi