qemu_mac: Check for existing env vars now more universal
qemu_mac: Check for existing env vars now more universal

hioa-cs/IncludeOS,AndreasAakesson/IncludeOS,AndreasAakesson/IncludeOS,mnordsletten/IncludeOS,alfred-bratterud/IncludeOS,hioa-cs/IncludeOS,AnnikaH/IncludeOS,mnordsletten/IncludeOS,mnordsletten/IncludeOS,alfred-bratterud/IncludeOS,mnordsletten/IncludeOS,alfred-bratterud/IncludeOS,AnnikaH/IncludeOS,alfred-bratterud/IncludeOS,AndreasAakesson/IncludeOS,ingve/IncludeOS,AndreasAakesson/IncludeOS,ingve/IncludeOS,hioa-cs/IncludeOS,ingve/IncludeOS,AndreasAakesson/IncludeOS,ingve/IncludeOS,mnordsletten/IncludeOS,AnnikaH/IncludeOS,hioa-cs/IncludeOS,mnordsletten/IncludeOS,hioa-cs/IncludeOS,AnnikaH/IncludeOS,AnnikaH/IncludeOS,alfred-bratterud/IncludeOS,ingve/IncludeOS,AndreasAakesson/IncludeOS