Fix Python compile errors with overloading and varargs

Fixes wrapping overloaded functions/constructors where a vararg
function is declared after a non-vararg function.
This is a long standing bug in the Python layer exposed since fastunpack
was turned on by default.

Examples/test-suite/varargs_overload.i

@@ -44,3 +44,47 @@ const char *vararg_over4(int i) {
   return buffer;
 }
 %}
+
+
+// Same as above but non-vararg function declared first
+
+%inline %{
+const char *vararg_over6(int i) {
+  static char buffer[256];
+  sprintf(buffer, "%d", i);
+  return buffer;
+}
+const char *vararg_over6(const char *fmt, ...) {
+  return fmt;
+}
+
+const char *vararg_over7(int i, double j) {
+  static char buffer[256];
+  sprintf(buffer, "%d %g", i, j);
+  return buffer;
+}
+const char *vararg_over7(const char *fmt, ...) {
+  return fmt;
+}
+
+const char *vararg_over8(int i, double j, const char *s) {
+  static char buffer[256];
+  sprintf(buffer, "%d %g %s", i, j, s);
+  return buffer;
+}
+const char *vararg_over8(const char *fmt, ...) {
+  return fmt;
+}
+%}
+
+%varargs(int mode = 0) vararg_over9;
+%inline %{
+const char *vararg_over9(int i) {
+  static char buffer[256];
+  sprintf(buffer, "%d", i);
+  return buffer;
+}
+const char *vararg_over9(const char *fmt, ...) {
+  return fmt;
+}
+%}