Make mktuple consistent with mklist to get rid of Coverity warnings. Also use…

Make mktuple consistent with mklist to get rid of Coverity warnings.  Also use macro version of SetItem since we know everything is setup.

Python/modsupport.c

@@ -218,7 +218,7 @@ do_mklist(const char **p_format, va_list *p_va, int endchar, int n)
 			Py_INCREF(Py_None);
 			w = Py_None;
 		}
-		PyList_SetItem(v, i, w);
+		PyList_SET_ITEM(v, i, w);
 	}
 
 	if (itemfailed) {
@@ -232,7 +232,6 @@ do_mklist(const char **p_format, va_list *p_va, int endchar, int n)
 				"Unmatched paren in format");
 		return NULL;
 	}
-
 	if (endchar)
 		++*p_format;
 	return v;
@@ -268,20 +267,21 @@ do_mktuple(const char **p_format, va_list *p_va, int endchar, int n)
 			Py_INCREF(Py_None);
 			w = Py_None;
 		}
-		PyTuple_SetItem(v, i, w);
+		PyTuple_SET_ITEM(v, i, w);
 	}
-	if (v != NULL && **p_format != endchar) {
+	if (itemfailed) {
+		/* do_mkvalue() should have already set an error */
+		Py_DECREF(v);
+		return NULL;
+	}
+	if (**p_format != endchar) {
 		Py_DECREF(v);
-		v = NULL;
 		PyErr_SetString(PyExc_SystemError,
 				"Unmatched paren in format");
+		return NULL;
 	}
-	else if (endchar)
+	if (endchar)
 		++*p_format;
-	if (itemfailed) {
-		Py_DECREF(v);
-		v = NULL;
-	}
 	return v;
 }