zZzzZ. — /usr/include/bits

Editing: time64.h

/* bits/time64.h -- underlying types for __time64_t.  Generic version.
   Copyright (C) 2018-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _BITS_TYPES_H
# error "Never include <bits/time64.h> directly; use <sys/types.h> instead."
#endif

#ifndef	_BITS_TIME64_H
#define	_BITS_TIME64_H	1

/* Define __TIME64_T_TYPE so that it is always a 64-bit type.  */

#if __TIMESIZE == 64
/* If we already have 64-bit time type then use it.  */
# define __TIME64_T_TYPE		__TIME_T_TYPE
#else
/* Define a 64-bit time type alongsize the 32-bit one.  */
# define __TIME64_T_TYPE		__SQUAD_TYPE
#endif

#endif /* bits/time64.h */