Issue #5915: Implement PEP 383, Non-decodable Bytes in
System Character Interfaces.
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 01bc235..4c77900 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -419,6 +419,9 @@
 /* Define this if you have the makedev macro. */
 #undef HAVE_MAKEDEV
 
+/* Define to 1 if you have the `mbrtowc' function. */
+#undef HAVE_MBRTOWC
+
 /* Define to 1 if you have the `memmove' function. */
 #undef HAVE_MEMMOVE