Upstream QEMU recommends to use '-display none' as opposed to
'-nographic' -- which is a "legacy option that does a whole bunch of
confusing stuff" (thanks Peter Maydell).
Upstream libguestfs already made the switch [1] in DEC-2013.
[1] https://github.com/libguestfs/libguestfs/commit/
7a41f5c1 -- "launch:
switch from -nographic to -display none "
declare -a argv
i=0
argv[$((i++))]="$qemu"
-argv[$((i++))]="-nographic"
+argv[$((i++))]="-display"
+argv[$((i++))]="none"
argv[$((i++))]="-nodefconfig"
argv[$((i++))]="-nodefaults"
argv[$((i++))]="-machine"