Bug #46042: backported the fix for the valgrind warning from 5.1

strings/strmake.c

@@ -41,8 +41,8 @@ char *strmake(register char *dst, register const char *src, uint length)
     write a character rather than '\0' as this makes spotting these
     problems in the results easier.
   */
-  uint n= strlen(src) + 1;
-  if (n <= length)
+  uint n= 0;
+  while (n < length && src[n++]);
   memset(dst + n, (int) 'Z', length - n + 1);
 #endif