- Added possibility to turn off mainloop event handling
- Check interrupts even when not handling events
- Be more carefulabout which events we want
- Use different method to determine fg/bg
macstrerror - strerror which uses 'Estr' resource to convert numerical
MacOS errors to strings.
PyErr_Mac - Raise exception with MacOS error in string form.
PyMac_Idle - better idle-loop routine, which allows the user to
switch applications.