diff --git a/libcxx/src/include/config_elast.h b/libcxx/src/include/config_elast.h
--- a/libcxx/src/include/config_elast.h
+++ b/libcxx/src/include/config_elast.h
@@ -35,6 +35,8 @@
 // No _LIBCPP_ELAST needed on Apple
 #elif defined(__sun__)
 #define _LIBCPP_ELAST ESTALE
+#elif defined(__MVS__)
+#define _LIBCPP_ELAST 1160
 #elif defined(_LIBCPP_MSVCRT_LIKE)
 #define _LIBCPP_ELAST (_sys_nerr - 1)
 #else