SF bug #488687 reported by Neal Norwitz

The error for assignment to __debug__ used ste->ste_opt_lineno instead
of n->n_lineno.  The latter was at best incorrect; often the slot was
uninitialized.  Two fixes here: Use the correct lineno for the error.
Initialize ste_opt_lineno in PySymtable_New(); while there are no
current cases where it is referenced unless it has already been
assigned to, there is no harm in initializing it.

Python/compile.c

@@ -5464,7 +5464,7 @@ symtable_assign(struct symtable *st, node *n, int def_flag)
 				PyErr_SetString(PyExc_SyntaxError, 
 						ASSIGN_DEBUG);
 				PyErr_SyntaxLocation(st->st_filename,
-					     st->st_cur->ste_opt_lineno);
+						     n->n_lineno);
 				st->st_errors++;
 			}
 			symtable_add_def(st, STR(tmp), DEF_LOCAL | def_flag);

Python/symtable.c

@@ -45,6 +45,7 @@ PySymtableEntry_New(struct symtable *st, char *name, int type, int lineno)
 	ste->ste_children = v;
 
 	ste->ste_optimized = 0;
+	ste->ste_opt_lineno = 0;
 	ste->ste_lineno = lineno;
 	switch (type) {
 	case funcdef: