Add a guard to compat (for now) that will crash if the LC_CYTPE isn't
ISO-8859-1 (aka Latin-1) when running under python3. We definitely
need this for handling argv safely (with at least python 3.7), and
since we're planning to require this arrangement anyway, let's start
now.
Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>