Do not declare asctime_r and ctime_r for C2X

[Paul Eggert]

On 5/13/21 5:39 PM, Joseph Myers wrote:
> The same change that removed those two functions from C2X also marked
> asctime and ctime as deprecated (reflecting how POSIX shows them as
> obsolescent), i.e. using the [[deprecated]] attribute in the
> prototypes shown in C2X.  It's less clear if we should explicitly
> deprecate those functions like that in the glibc headers

Sounds like that's just a quality-of-implementation issue. My vote would 
be to deprecate them in the glibc headers, as they're asking for trouble 
(buffer overrun etc.) with 64-bit time_t.