Re: Allow to_date() and to_timestamp() to accept localized names

I have some couple picky notes.

> +     if (name_len != norm_len)
> +             pfree(norm_name);

I'm not sure here. Is it save to assume that if it was allocated a new
norm_name name_len and norm_len always will differ?

>  static const char *const months_full[] = {
>       "January", "February", "March", "April", "May", "June", "July",
> -     "August", "September", "October", "November", "December", NULL
> +     "August", "September", "October", "November", "December"
>  };

Unfortunately I didn't see from the patch why it was necessary to remove
last null element from months_full, days_short, adbc_strings,
adbc_strings_long and other arrays. I think it is not good because
unnecessarily increases the patch and adds code like the following:

> +                             from_char_seq_search(&value, &s, months, localized_names,
> +                                                                      ONE_UPPER, MAX_MON_LEN, n, have_error,
> +                                                                      lengthof(months_full));

Here it passes "months" from datetime.c to from_char_seq_search() and
calculates its length using "months_full" array from formatting.c.