Added PyMac_GetPythonDir routine which obtains python home directory

from an alias resource (or from the user). Note: this uses a dialog
resource so there's an accompanying change in the resource file.

Mac/Include/macglue.h

@@ -42,6 +42,8 @@ void PyMac_HandleEvent Py_PROTO((EventRecord *));	/* Handle one event, if possib
 
 int PyMac_Idle(void);				/* Idle routine */
 
+char *PyMac_GetPythonDir();					/* Return the name of the python dir */
+
 int PyMac_GetOSType(PyObject *, OSType *);	/* argument parser for OSType */
 PyObject *PyMac_BuildOSType(OSType);		/* Convert OSType to PyObject */