[klibc] include: [limits.h] define MB_LEN_MAX

Susv3 tells it shall be defined, encountered in util-linux.

Signed-off-by: maximilian attems <max@stro.at>
diff --git a/usr/include/limits.h b/usr/include/limits.h
index 80b2c1f..464420a 100644
--- a/usr/include/limits.h
+++ b/usr/include/limits.h
@@ -5,6 +5,9 @@
 #ifndef _LIMITS_H
 #define _LIMITS_H
 
+/* No multibyte characters seen */
+#define MB_LEN_MAX 1
+
 #define OPEN_MAX        256
 
 #define CHAR_BIT	8