New routines:

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.

Mac/Include/macglue.h

@@ -0,0 +1,3 @@
+char *macstrerror PROTO((int));				/* strerror with mac errors */
+object *PyErr_Mac PROTO((object *, int));	/* Exception with a mac error */
+int PyMac_Idle PROTO((void));				/* Idle routine */

Mac/Python/macglue.c

@@ -0,0 +1,86 @@
+/*
+** macglue - A couple of mac-specific routines often needed.
+**
+** Jack Jansen, CWI, 1994.
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "Python.h"
+#include "macglue.h"
+
+#include <OSUtils.h> /* for Set(Current)A5 */
+#include <Resources.h>
+#include <Memory.h>
+#include <Events.h>
+#include <Windows.h>
+#include <Desk.h>
+
+/* Replace strerror with something that might work */
+char *macstrerror(int err)
+{
+	static char buf[256];
+	Handle h;
+	char *str;
+	
+	h = GetResource('Estr', err);
+	if ( h ) {
+		HLock(h);
+		str = (char *)*h;
+		memcpy(buf, str+1, (unsigned char)str[0]);
+		HUnlock(h);
+		ReleaseResource(h);
+	} else {
+		sprintf(buf, "Mac OS error code %d", err);
+	}
+	return buf;
+}
+
+/* Set a MAC-specific error from errno, and return NULL; return None if no error */
+PyObject * 
+PyErr_Mac(object *eobj, int err)
+{
+	char *msg;
+	PyObject *v;
+	Handle h;
+	
+	if (err == 0) {
+		Py_INCREF(Py_None);
+		return Py_None;
+	}
+	msg = macstrerror(err);
+	v = Py_BuildValue("(is)", err, msg);
+	PyErr_SetObject(eobj, v);
+	Py_DECREF(v);
+	return NULL;
+}
+
+/*
+** Idle routine for busy-wait loops.
+** This is rather tricky: if we see an event we check whether it is
+** for somebody else (i.e. a click outside our windows) and, if so,
+** we pass the event on (so the user can switch processes). However,
+** by doing this we loose events meant for our windows. Too bad, I guess...
+*/
+int
+PyMac_Idle()
+{
+	EventRecord ev;
+	WindowPtr wp;
+
+#if 0
+	SystemTask();
+	if ( intrcheck() )
+		return 0;
+	if ( GetNextEvent(0xffff, &ev) ) {
+		if ( ev.what == mouseDown ) {
+			if ( FindWindow(ev.where, &wp) == inSysWindow )
+				SystemClick(&ev, wp);
+		}
+	}
+#endif
+	return 1;
+}
+