Issue #18571: Implementation of the PEP 446: file descriptors and file handles
are now created non-inheritable; add functions os.get/set_inheritable(),
os.get/set_handle_inheritable() and socket.socket.get/set_inheritable().
diff --git a/pyconfig.h.in b/pyconfig.h.in
index 6dd9250..65205e4 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -193,6 +193,9 @@
/* Define to 1 if you have the `dup2' function. */
#undef HAVE_DUP2
+/* Define to 1 if you have the `dup3' function. */
+#undef HAVE_DUP3
+
/* Defined when any dynamic module loading is enabled. */
#undef HAVE_DYNAMIC_LOADING