Bump tzcode from 2016g to 2022a*.

Upstream has renamed tzsetlcl to tzset_unlocked. As bionic's
implementation of tzset_unlock differs from upstream, these changes were
skipped.

Also, upstream has removed constants (SECSPERMIN, etc) from tzfile.h. As
they are used in strptime.c, I've decided to leave them in tzfile.h and
to not bring them into strptime.c.

HAVE_TZNAME and USG_COMPAT flags semantics were updated, thus setting
their values to 2 in Android.bp file. See
https://github.com/eggert/tz/commit/1a27ec76bc436a64070461bbbf28e0511c7cf3b8

* https://github.com/eggert/tz/commit/4742526b7e8a0f26adaf068c9f5c0bc0870909e7
and https://github.com/eggert/tz/commit/0e8f0b06ac2f65d0c54a91121da09c8662cd88e6
were picked up, which are not part of 2022a.

Changes were applied using following commands:
  1) Checkout tzcode repo
  2) Prepare patches for all tzcode file using
    git diff 2016g 2021e -- <file-name> > <file-name-patch>
  3) Apply these patches to files in bionic using
    patch -p1 <file-name> <file-name-patch>

Bug: 25413083
Test: CtsLibcoreTestCases
Test: CtsLibcoreOjTestCases
Test: CtsBionicTestCases

Change-Id: I9aba4cbeab30171a32f94d20c8e4057804a4c01f
diff --git a/libc/tzcode/private.h b/libc/tzcode/private.h
index 941e91b..4c03324 100644
--- a/libc/tzcode/private.h
+++ b/libc/tzcode/private.h
@@ -1,3 +1,5 @@
+/* Private header for tzdb code.  */
+
 #ifndef PRIVATE_H
 
 #define PRIVATE_H
@@ -15,6 +17,17 @@
 ** Thank you!
 */
 
+/*
+** zdump has been made independent of the rest of the time
+** conversion package to increase confidence in the verification it provides.
+** You can use zdump to help in verifying other implementations.
+** To do this, compile with -DUSE_LTZ=0 and link without the tz library.
+*/
+#ifndef USE_LTZ
+# define USE_LTZ 1
+#endif
+
+/* This string was in the Factory zone through version 2016f.  */
 #define GRANDPARENTED	"Local time zone must be set--see zic manual page"
 
 /*
@@ -26,26 +39,53 @@
 #define HAVE_DECL_ASCTIME_R 1
 #endif
 
+#if !defined HAVE_GENERIC && defined __has_extension
+# if __has_extension(c_generic_selections)
+#  define HAVE_GENERIC 1
+# else
+#  define HAVE_GENERIC 0
+# endif
+#endif
+/* _Generic is buggy in pre-4.9 GCC.  */
+#if !defined HAVE_GENERIC && defined __GNUC__
+# define HAVE_GENERIC (4 < __GNUC__ + (9 <= __GNUC_MINOR__))
+#endif
+#ifndef HAVE_GENERIC
+# define HAVE_GENERIC (201112 <= __STDC_VERSION__)
+#endif
+
 #ifndef HAVE_GETTEXT
 #define HAVE_GETTEXT		0
 #endif /* !defined HAVE_GETTEXT */
 
 #ifndef HAVE_INCOMPATIBLE_CTIME_R
 #define HAVE_INCOMPATIBLE_CTIME_R	0
-#endif /* !defined INCOMPATIBLE_CTIME_R */
+#endif
 
 #ifndef HAVE_LINK
 #define HAVE_LINK		1
 #endif /* !defined HAVE_LINK */
 
+#ifndef HAVE_MALLOC_ERRNO
+#define HAVE_MALLOC_ERRNO 1
+#endif
+
 #ifndef HAVE_POSIX_DECLS
 #define HAVE_POSIX_DECLS 1
 #endif
 
+#ifndef HAVE_STDBOOL_H
+#define HAVE_STDBOOL_H (199901 <= __STDC_VERSION__)
+#endif
+
 #ifndef HAVE_STRDUP
 #define HAVE_STRDUP 1
 #endif
 
+#ifndef HAVE_STRTOLL
+#define HAVE_STRTOLL 1
+#endif
+
 #ifndef HAVE_SYMLINK
 #define HAVE_SYMLINK		1
 #endif /* !defined HAVE_SYMLINK */
@@ -54,10 +94,6 @@
 #define HAVE_SYS_STAT_H		1
 #endif /* !defined HAVE_SYS_STAT_H */
 
-#ifndef HAVE_SYS_WAIT_H
-#define HAVE_SYS_WAIT_H		1
-#endif /* !defined HAVE_SYS_WAIT_H */
-
 #ifndef HAVE_UNISTD_H
 #define HAVE_UNISTD_H		1
 #endif /* !defined HAVE_UNISTD_H */
@@ -75,22 +111,37 @@
 #define ctime_r _incompatible_ctime_r
 #endif /* HAVE_INCOMPATIBLE_CTIME_R */
 
-/* Enable tm_gmtoff and tm_zone on GNUish systems.  */
+/* Enable tm_gmtoff, tm_zone, and environ on GNUish systems.  */
 #define _GNU_SOURCE 1
-/* Fix asctime_r on Solaris 10.  */
+/* Fix asctime_r on Solaris 11.  */
 #define _POSIX_PTHREAD_SEMANTICS 1
-/* Enable strtoimax on Solaris 10.  */
+/* Enable strtoimax on pre-C99 Solaris 11.  */
 #define __EXTENSIONS__ 1
 
+/* To avoid having 'stat' fail unnecessarily with errno == EOVERFLOW,
+   enable large files on GNUish systems ...  */
+#ifndef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 64
+#endif
+/* ... and on AIX ...  */
+#define _LARGE_FILES 1
+/* ... and enable large inode numbers on Mac OS X 10.5 and later.  */
+#define _DARWIN_USE_64_BIT_INODE 1
+
 /*
 ** Nested includes
 */
 
-/* Avoid clashes with NetBSD by renaming NetBSD's declarations.  */
+/* Avoid clashes with NetBSD by renaming NetBSD's declarations.
+   If defining the 'timezone' variable, avoid a clash with FreeBSD's
+   'timezone' function by renaming its declaration.  */
 #define localtime_rz sys_localtime_rz
 #define mktime_z sys_mktime_z
 #define posix2time_z sys_posix2time_z
 #define time2posix_z sys_time2posix_z
+#if defined USG_COMPAT && USG_COMPAT == 2
+# define timezone sys_timezone
+#endif
 #define timezone_t sys_timezone_t
 #define tzalloc sys_tzalloc
 #define tzfree sys_tzfree
@@ -99,21 +150,30 @@
 #undef mktime_z
 #undef posix2time_z
 #undef time2posix_z
+#if defined USG_COMPAT && USG_COMPAT == 2
+# undef timezone
+#endif
 #undef timezone_t
 #undef tzalloc
 #undef tzfree
 
-#include "sys/types.h"	/* for time_t */
-#include "stdio.h"
-#include "string.h"
-#include "limits.h"	/* for CHAR_BIT et al. */
-#include "stdlib.h"
+#include <sys/types.h>	/* for time_t */
+#include <string.h>
+#include <limits.h>	/* for CHAR_BIT et al. */
+#include <stdlib.h>
 
-#include "errno.h"
+#include <errno.h>
+
+#ifndef EINVAL
+# define EINVAL ERANGE
+#endif
 
 #ifndef ENAMETOOLONG
 # define ENAMETOOLONG EINVAL
 #endif
+#ifndef ENOMEM
+# define ENOMEM EINVAL
+#endif
 #ifndef ENOTSUP
 # define ENOTSUP EINVAL
 #endif
@@ -122,22 +182,11 @@
 #endif
 
 #if HAVE_GETTEXT
-#include "libintl.h"
+#include <libintl.h>
 #endif /* HAVE_GETTEXT */
 
-#if HAVE_SYS_WAIT_H
-#include <sys/wait.h>	/* for WIFEXITED and WEXITSTATUS */
-#endif /* HAVE_SYS_WAIT_H */
-
-#ifndef WIFEXITED
-#define WIFEXITED(status)	(((status) & 0xff) == 0)
-#endif /* !defined WIFEXITED */
-#ifndef WEXITSTATUS
-#define WEXITSTATUS(status)	(((status) >> 8) & 0xff)
-#endif /* !defined WEXITSTATUS */
-
 #if HAVE_UNISTD_H
-#include "unistd.h"	/* for F_OK, R_OK, and other POSIX goodness */
+#include <unistd.h>	/* for R_OK, and other POSIX goodness */
 #endif /* HAVE_UNISTD_H */
 
 #ifndef HAVE_STRFTIME_L
@@ -148,31 +197,49 @@
 # endif
 #endif
 
-#ifndef F_OK
-#define F_OK	0
-#endif /* !defined F_OK */
+#ifndef USG_COMPAT
+# ifndef _XOPEN_VERSION
+#  define USG_COMPAT 0
+# else
+#  define USG_COMPAT 1
+# endif
+#endif
+
+#ifndef HAVE_TZNAME
+# if _POSIX_VERSION < 198808 && !USG_COMPAT
+#  define HAVE_TZNAME 0
+# else
+#  define HAVE_TZNAME 1
+# endif
+#endif
+
+#ifndef ALTZONE
+# if defined __sun || defined _M_XENIX
+#  define ALTZONE 1
+# else
+#  define ALTZONE 0
+# endif
+#endif
+
 #ifndef R_OK
 #define R_OK	4
 #endif /* !defined R_OK */
 
-/* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
-#define is_digit(c) ((unsigned)(c) - '0' <= 9)
-
 /*
 ** Define HAVE_STDINT_H's default value here, rather than at the
-** start, since __GLIBC__'s value depends on previously-included
-** files.
-** (glibc 2.1 and later have stdint.h, even with pre-C99 compilers.)
+** start, since __GLIBC__ and INTMAX_MAX's values depend on
+** previously-included files.  glibc 2.1 and Solaris 10 and later have
+** stdint.h, even with pre-C99 compilers.
 */
 #ifndef HAVE_STDINT_H
 #define HAVE_STDINT_H \
    (199901 <= __STDC_VERSION__ \
     || 2 < __GLIBC__ + (1 <= __GLIBC_MINOR__)	\
-    || __CYGWIN__)
+    || __CYGWIN__ || INTMAX_MAX)
 #endif /* !defined HAVE_STDINT_H */
 
 #if HAVE_STDINT_H
-#include "stdint.h"
+#include <stdint.h>
 #endif /* !HAVE_STDINT_H */
 
 #ifndef HAVE_INTTYPES_H
@@ -208,14 +275,18 @@
 # endif
 #endif
 
-#ifndef SCNdFAST64
+#ifndef PRIdFAST64
 # if INT_FAST64_MAX == LLONG_MAX
-#  define SCNdFAST64 "lld"
+#  define PRIdFAST64 "lld"
 # else
-#  define SCNdFAST64 "ld"
+#  define PRIdFAST64 "ld"
 # endif
 #endif
 
+#ifndef SCNdFAST64
+# define SCNdFAST64 PRIdFAST64
+#endif
+
 #ifndef INT_FAST32_MAX
 # if INT_MAX >> 31 == 0
 typedef long int_fast32_t;
@@ -231,15 +302,19 @@
 #ifndef INTMAX_MAX
 # ifdef LLONG_MAX
 typedef long long intmax_t;
-#  define strtoimax strtoll
+#  if HAVE_STRTOLL
+#   define strtoimax strtoll
+#  endif
 #  define INTMAX_MAX LLONG_MAX
 #  define INTMAX_MIN LLONG_MIN
 # else
 typedef long intmax_t;
-#  define strtoimax strtol
 #  define INTMAX_MAX LONG_MAX
 #  define INTMAX_MIN LONG_MIN
 # endif
+# ifndef strtoimax
+#  define strtoimax strtol
+# endif
 #endif
 
 #ifndef PRIdMAX
@@ -250,6 +325,10 @@
 # endif
 #endif
 
+#ifndef UINT_FAST32_MAX
+typedef unsigned long uint_fast32_t;
+#endif
+
 #ifndef UINT_FAST64_MAX
 # if defined ULLONG_MAX || defined __LONG_LONG_MAX__
 typedef unsigned long long uint_fast64_t;
@@ -289,19 +368,21 @@
 #define SIZE_MAX ((size_t) -1)
 #endif
 
-#if 2 < __GNUC__ + (96 <= __GNUC_MINOR__)
-# define ATTRIBUTE_CONST __attribute__ ((const))
-# define ATTRIBUTE_PURE __attribute__ ((__pure__))
-# define ATTRIBUTE_FORMAT(spec) __attribute__ ((__format__ spec))
+#if 3 <= __GNUC__
+# define ATTRIBUTE_CONST __attribute__((const))
+# define ATTRIBUTE_MALLOC __attribute__((__malloc__))
+# define ATTRIBUTE_PURE __attribute__((__pure__))
+# define ATTRIBUTE_FORMAT(spec) __attribute__((__format__ spec))
 #else
 # define ATTRIBUTE_CONST /* empty */
+# define ATTRIBUTE_MALLOC /* empty */
 # define ATTRIBUTE_PURE /* empty */
 # define ATTRIBUTE_FORMAT(spec) /* empty */
 #endif
 
 #if !defined _Noreturn && __STDC_VERSION__ < 201112
 # if 2 < __GNUC__ + (8 <= __GNUC_MINOR__)
-#  define _Noreturn __attribute__ ((__noreturn__))
+#  define _Noreturn __attribute__((__noreturn__))
 # else
 #  define _Noreturn
 # endif
@@ -315,6 +396,23 @@
 ** Workarounds for compilers/systems.
 */
 
+#ifndef EPOCH_LOCAL
+# define EPOCH_LOCAL 0
+#endif
+#ifndef EPOCH_OFFSET
+# define EPOCH_OFFSET 0
+#endif
+#ifndef RESERVE_STD_EXT_IDS
+# define RESERVE_STD_EXT_IDS 0
+#endif
+
+/* If standard C identifiers with external linkage (e.g., localtime)
+   are reserved and are not already being renamed anyway, rename them
+   as if compiling with '-Dtime_tz=time_t'.  */
+#if !defined time_tz && RESERVE_STD_EXT_IDS && USE_LTZ
+# define time_tz time_t
+#endif
+
 /*
 ** Compile with -Dtime_tz=T to build the tz package with a private
 ** time_t type equivalent to T rather than the system-supplied time_t.
@@ -322,13 +420,24 @@
 ** (e.g., time_t wider than 'long', or unsigned time_t) even on
 ** typical platforms.
 */
-#ifdef time_tz
-# ifdef LOCALTIME_IMPLEMENTATION
+#if defined time_tz || EPOCH_LOCAL || EPOCH_OFFSET != 0
+# define TZ_TIME_T 1
+#else
+# define TZ_TIME_T 0
+#endif
+
+#if defined LOCALTIME_IMPLEMENTATION && TZ_TIME_T
 static time_t sys_time(time_t *x) { return time(x); }
-# endif
+#endif
+
+#if TZ_TIME_T
 
 typedef time_tz tz_time_t;
 
+# undef  asctime
+# define asctime tz_asctime
+# undef  asctime_r
+# define asctime_r tz_asctime_r
 # undef  ctime
 # define ctime tz_ctime
 # undef  ctime_r
@@ -355,6 +464,8 @@
 # define posix2time tz_posix2time
 # undef  posix2time_z
 # define posix2time_z tz_posix2time_z
+# undef  strftime
+# define strftime tz_strftime
 # undef  time
 # define time tz_time
 # undef  time2posix
@@ -375,12 +486,36 @@
 # define tzfree tz_tzfree
 # undef  tzset
 # define tzset tz_tzset
-# undef  tzsetwall
-# define tzsetwall tz_tzsetwall
+# if HAVE_STRFTIME_L
+#  undef  strftime_l
+#  define strftime_l tz_strftime_l
+# endif
+# if HAVE_TZNAME
+#  undef  tzname
+#  define tzname tz_tzname
+# endif
+# if USG_COMPAT
+#  undef  daylight
+#  define daylight tz_daylight
+#  undef  timezone
+#  define timezone tz_timezone
+# endif
+# if ALTZONE
+#  undef  altzone
+#  define altzone tz_altzone
+# endif
 
+char *asctime(struct tm const *);
+char *asctime_r(struct tm const *restrict, char *restrict);
 char *ctime(time_t const *);
 char *ctime_r(time_t const *, char *);
-double difftime(time_t, time_t);
+double difftime(time_t, time_t) ATTRIBUTE_CONST;
+size_t strftime(char *restrict, size_t, char const *restrict,
+		struct tm const *restrict);
+# if HAVE_STRFTIME_L
+size_t strftime_l(char *restrict, size_t, char const *restrict,
+		  struct tm const *restrict, locale_t);
+# endif
 struct tm *gmtime(time_t const *);
 struct tm *gmtime_r(time_t const *restrict, struct tm *restrict);
 struct tm *localtime(time_t const *);
@@ -394,18 +529,26 @@
 extern char *asctime_r(struct tm const *restrict, char *restrict);
 #endif
 
-#if !HAVE_POSIX_DECLS
-# ifdef USG_COMPAT
-#  ifndef timezone
-extern long timezone;
-#  endif
-#  ifndef daylight
-extern int daylight;
-#  endif
+#ifndef HAVE_DECL_ENVIRON
+# if defined environ || defined __USE_GNU
+#  define HAVE_DECL_ENVIRON 1
+# else
+#  define HAVE_DECL_ENVIRON 0
 # endif
 #endif
 
-#if defined ALTZONE && !defined altzone
+#if !HAVE_DECL_ENVIRON
+extern char **environ;
+#endif
+
+#if 2 <= HAVE_TZNAME + (TZ_TIME_T || !HAVE_POSIX_DECLS)
+extern char *tzname[];
+#endif
+#if 2 <= USG_COMPAT + (TZ_TIME_T || !HAVE_POSIX_DECLS)
+extern long timezone;
+extern int daylight;
+#endif
+#if 2 <= ALTZONE + (TZ_TIME_T || !HAVE_POSIX_DECLS)
 extern long altzone;
 #endif
 
@@ -415,25 +558,22 @@
 */
 
 #ifdef STD_INSPIRED
-# if !defined tzsetwall || defined time_tz
-void tzsetwall(void);
-# endif
-# if !defined offtime || defined time_tz
+# if TZ_TIME_T || !defined offtime
 struct tm *offtime(time_t const *, long);
 # endif
-# if !defined timegm || defined time_tz
+# if TZ_TIME_T || !defined timegm
 time_t timegm(struct tm *);
 # endif
-# if !defined timelocal || defined time_tz
+# if TZ_TIME_T || !defined timelocal
 time_t timelocal(struct tm *);
 # endif
-# if !defined timeoff || defined time_tz
+# if TZ_TIME_T || !defined timeoff
 time_t timeoff(struct tm *, long);
 # endif
-# if !defined time2posix || defined time_tz
+# if TZ_TIME_T || !defined time2posix
 time_t time2posix(time_t);
 # endif
-# if !defined posix2time || defined time_tz
+# if TZ_TIME_T || !defined posix2time
 time_t posix2time(time_t);
 # endif
 #endif
@@ -467,10 +607,10 @@
 timezone_t tzalloc(char const *);
 void tzfree(timezone_t);
 # ifdef STD_INSPIRED
-#  if !defined posix2time_z || defined time_tz
+#  if TZ_TIME_T || !defined posix2time_z
 time_t posix2time_z(timezone_t, time_t) ATTRIBUTE_PURE;
 #  endif
-#  if !defined time2posix_z || defined time_tz
+#  if TZ_TIME_T || !defined time2posix_z
 time_t time2posix_z(timezone_t, time_t) ATTRIBUTE_PURE;
 #  endif
 # endif
@@ -480,22 +620,16 @@
 ** Finally, some convenience items.
 */
 
-#if __STDC_VERSION__ < 199901
+#if HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
 # define true 1
 # define false 0
 # define bool int
-#else
-# include <stdbool.h>
 #endif
 
-#ifndef TYPE_BIT
-#define TYPE_BIT(type)	(sizeof (type) * CHAR_BIT)
-#endif /* !defined TYPE_BIT */
-
-#ifndef TYPE_SIGNED
+#define TYPE_BIT(type)	(sizeof(type) * CHAR_BIT)
 #define TYPE_SIGNED(type) (((type) -1) < 0)
-#endif /* !defined TYPE_SIGNED */
-
 #define TWOS_COMPLEMENT(t) ((t) ~ (t) 0 < 0)
 
 /* Max and min values of the integer type T, of which only the bottom
@@ -507,11 +641,34 @@
 #define MINVAL(t, b)						\
   ((t) (TYPE_SIGNED(t) ? - TWOS_COMPLEMENT(t) - MAXVAL(t, b) : 0))
 
-/* The minimum and maximum finite time values.  This assumes no padding.  */
-static time_t const time_t_min = MINVAL(time_t, TYPE_BIT(time_t));
-static time_t const time_t_max = MAXVAL(time_t, TYPE_BIT(time_t));
+/* The extreme time values, assuming no padding.  */
+#define TIME_T_MIN_NO_PADDING MINVAL(time_t, TYPE_BIT(time_t))
+#define TIME_T_MAX_NO_PADDING MAXVAL(time_t, TYPE_BIT(time_t))
 
-#ifndef INT_STRLEN_MAXIMUM
+/* The extreme time values.  These are macros, not constants, so that
+   any portability problems occur only when compiling .c files that use
+   the macros, which is safer for applications that need only zdump and zic.
+   This implementation assumes no padding if time_t is signed and
+   either the compiler lacks support for _Generic or time_t is not one
+   of the standard signed integer types.  */
+#if HAVE_GENERIC
+# define TIME_T_MIN \
+    _Generic((time_t) 0, \
+	     signed char: SCHAR_MIN, short: SHRT_MIN, \
+	     int: INT_MIN, long: LONG_MIN, long long: LLONG_MIN, \
+	     default: TIME_T_MIN_NO_PADDING)
+# define TIME_T_MAX \
+    (TYPE_SIGNED(time_t) \
+     ? _Generic((time_t) 0, \
+		signed char: SCHAR_MAX, short: SHRT_MAX, \
+		int: INT_MAX, long: LONG_MAX, long long: LLONG_MAX, \
+		default: TIME_T_MAX_NO_PADDING)			    \
+     : (time_t) -1)
+#else
+# define TIME_T_MIN TIME_T_MIN_NO_PADDING
+# define TIME_T_MAX TIME_T_MAX_NO_PADDING
+#endif
+
 /*
 ** 302 / 1000 is log10(2.0) rounded up.
 ** Subtract one for the sign bit if the type is signed;
@@ -521,13 +678,12 @@
 #define INT_STRLEN_MAXIMUM(type) \
 	((TYPE_BIT(type) - TYPE_SIGNED(type)) * 302 / 1000 + \
 	1 + TYPE_SIGNED(type))
-#endif /* !defined INT_STRLEN_MAXIMUM */
 
 /*
 ** INITIALIZE(x)
 */
 
-#ifdef lint
+#ifdef GCC_LINT
 # define INITIALIZE(x)	((x) = 0)
 #else
 # define INITIALIZE(x)
@@ -537,19 +693,30 @@
 # define UNINIT_TRAP 0
 #endif
 
+#ifdef DEBUG
+# define UNREACHABLE() abort()
+#elif 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
+# define UNREACHABLE() __builtin_unreachable()
+#elif defined __has_builtin
+# if __has_builtin(__builtin_unreachable)
+#  define UNREACHABLE() __builtin_unreachable()
+# endif
+#endif
+#ifndef UNREACHABLE
+# define UNREACHABLE() ((void) 0)
+#endif
+
 /*
 ** For the benefit of GNU folk...
 ** '_(MSGID)' uses the current locale's message library string for MSGID.
 ** The default is to use gettext if available, and use MSGID otherwise.
 */
 
-#ifndef _
 #if HAVE_GETTEXT
 #define _(msgid) gettext(msgid)
 #else /* !HAVE_GETTEXT */
 #define _(msgid) msgid
 #endif /* !HAVE_GETTEXT */
-#endif /* !defined _ */
 
 #if !defined TZ_DOMAIN && defined HAVE_GETTEXT
 # define TZ_DOMAIN "tz"
@@ -562,24 +729,64 @@
 char *ctime_r(time_t const *, char *);
 #endif /* HAVE_INCOMPATIBLE_CTIME_R */
 
-#ifndef YEARSPERREPEAT
+/* Handy macros that are independent of tzfile implementation.  */
+
+#define SECSPERMIN	60
+#define MINSPERHOUR	60
+#define HOURSPERDAY	24
+#define DAYSPERWEEK	7
+#define DAYSPERNYEAR	365
+#define DAYSPERLYEAR	366
+#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
+#define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
+#define MONSPERYEAR	12
+
 #define YEARSPERREPEAT		400	/* years before a Gregorian repeat */
-#endif /* !defined YEARSPERREPEAT */
+#define DAYSPERREPEAT		((int_fast32_t) 400 * 365 + 100 - 4 + 1)
+#define SECSPERREPEAT		((int_fast64_t) DAYSPERREPEAT * SECSPERDAY)
+#define AVGSECSPERYEAR		(SECSPERREPEAT / YEARSPERREPEAT)
+
+#define TM_SUNDAY	0
+#define TM_MONDAY	1
+#define TM_TUESDAY	2
+#define TM_WEDNESDAY	3
+#define TM_THURSDAY	4
+#define TM_FRIDAY	5
+#define TM_SATURDAY	6
+
+#define TM_JANUARY	0
+#define TM_FEBRUARY	1
+#define TM_MARCH	2
+#define TM_APRIL	3
+#define TM_MAY		4
+#define TM_JUNE		5
+#define TM_JULY		6
+#define TM_AUGUST	7
+#define TM_SEPTEMBER	8
+#define TM_OCTOBER	9
+#define TM_NOVEMBER	10
+#define TM_DECEMBER	11
+
+#define TM_YEAR_BASE	1900
+#define TM_WDAY_BASE	TM_MONDAY
+
+#define EPOCH_YEAR	1970
+#define EPOCH_WDAY	TM_THURSDAY
+
+#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
 
 /*
-** The Gregorian year averages 365.2425 days, which is 31556952 seconds.
+** Since everything in isleap is modulo 400 (or a factor of 400), we know that
+**	isleap(y) == isleap(y % 400)
+** and so
+**	isleap(a + b) == isleap((a + b) % 400)
+** or
+**	isleap(a + b) == isleap(a % 400 + b % 400)
+** This is true even if % means modulo rather than Fortran remainder
+** (which is allowed by C89 but not by C99 or later).
+** We use this to avoid addition overflow problems.
 */
 
-#ifndef AVGSECSPERYEAR
-#define AVGSECSPERYEAR		31556952L
-#endif /* !defined AVGSECSPERYEAR */
-
-#ifndef SECSPERREPEAT
-#define SECSPERREPEAT		((int_fast64_t) YEARSPERREPEAT * (int_fast64_t) AVGSECSPERYEAR)
-#endif /* !defined SECSPERREPEAT */
-
-#ifndef SECSPERREPEAT_BITS
-#define SECSPERREPEAT_BITS	34	/* ceil(log2(SECSPERREPEAT)) */
-#endif /* !defined SECSPERREPEAT_BITS */
+#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
 
 #endif /* !defined PRIVATE_H */