diff --git a/wcsmbs/wcrtomb.c b/wcsmbs/wcrtomb.c
index 493e08f77d..43a2162500 100644
--- a/wcsmbs/wcrtomb.c
+++ b/wcsmbs/wcrtomb.c
@@ -20,6 +20,9 @@ Boston, MA 02111-1307, USA.  */
 #include <errno.h>
 #include <wchar.h>
 
+#ifndef EILSEQ
+#define EILSEQ EINVAL
+#endif
 
 size_t
 wcrtomb (s, wc, ps)
diff --git a/wcsmbs/wcsrtombs.c b/wcsmbs/wcsrtombs.c
index 612a86d437..487237fcad 100644
--- a/wcsmbs/wcsrtombs.c
+++ b/wcsmbs/wcsrtombs.c
@@ -20,6 +20,10 @@ Boston, MA 02111-1307, USA.  */
 #include <errno.h>
 #include <wchar.h>
 
+#ifndef EILSEQ
+#define EILSEQ EINVAL
+#endif
+
 
 size_t
 wcsrtombs (dst, src, len, ps)