Py_BuildValue(): Add "D" conversion to create a Python complex value from

a Py_complex C value.

Patch by Walter Dörwald.
This partially closes SF patch #407148.

Python/modsupport.c

@@ -286,6 +286,12 @@ do_mkvalue(char **p_format, va_list *p_va)
 			return PyFloat_FromDouble(
 				(double)va_arg(*p_va, va_double));
 
+#ifndef WITHOUT_COMPLEX
+		case 'D':
+			return PyComplex_FromCComplex(
+				*((Py_complex *)va_arg(*p_va, Py_complex *)));
+#endif /* WITHOUT_COMPLEX */
+
 		case 'c':
 		{
 			char p[1];