wchar_rep_t *const concat = obstack_alloc(&symbol_obstack, (len1 + len2 + 1) * sizeof(*concat));
memcpy(concat, s1->begin, len1 * sizeof(*concat));
wchar_rep_t *const concat = obstack_alloc(&symbol_obstack, (len1 + len2 + 1) * sizeof(*concat));
memcpy(concat, s1->begin, len1 * sizeof(*concat));