move strndup to libi3

src/util.c

@@ -415,27 +415,3 @@ void *memmem(const void *l, size_t l_len, const void *s, size_t s_len) {
 }
 
 #endif
-
-#if defined(__APPLE__)
-
-/*
- * Taken from FreeBSD
- * Returns a pointer to a new string which is a duplicate of the
- * string, but only copies at most n characters.
- *
- */
-char *strndup(const char *str, size_t n) {
-    size_t len;
-    char *copy;
-
-    for (len = 0; len < n && str[len]; len++)
-        continue;
-
-    if ((copy = malloc(len + 1)) == NULL)
-        return (NULL);
-    memcpy(copy, str, len);
-    copy[len] = '\0';
-    return (copy);
-}
-
-#endif