Y2038: make __tz_convert compatible with 64-bit-timeaaribaud/tmp

This implies that its callers be 64-bit-time compatible too.
It is done by creating 64-bit-time versions of these and
turning their original 32-bit-time versions into wrappers
(at a slight execution time cost).

The callers affected are:

  * localtime
  * localtime_r
  * ctime
  * ctime_r
  * gmtime
  * gmtime_r

Note that in time/tzfile.c we do not need to check for time_t
overflows anymore as introduced by commit fc79706a323 since we
now use internal_time_t.

1 files changed, 7 insertions, 10 deletions

diff --git a/time/tzfile.c b/time/tzfile.c
index d7e391c3a3..eddc0f825a 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -113,6 +113,9 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
   size_t tzspec_len;
   char *new = NULL;
 
+  _Static_assert (sizeof (time_t) == 8,
+		  "time_t must be eight bytes");
+
   _Static_assert (sizeof (__time64_t) == 8,
 		  "__time64_t must be eight bytes");
 
@@ -635,16 +638,10 @@ __tzfile_compute (__time64_t timer, int use_localtime,
 
 	  /* Convert to broken down structure.  If this fails do not
 	     use the string.  */
-	  {
-	    time_t truncated = timer;
-	    if (__glibc_unlikely (truncated != timer
-				  || ! __offtime (&truncated, 0, tp)))
-	      goto use_last;
-	  }
-
-	  /* Use the rules from the TZ string to compute the change.
-	     timer fits into time_t due to the truncation check
-	     above.  */
+	  if (__glibc_unlikely (! __offtime (timer, 0, tp)))
+	    goto use_last;
+
+	  /* Use the rules from the TZ string to compute the change.  */
 	  __tz_compute (timer, tp, 1);
 
 	  /* If tzspec comes from posixrules loaded by __tzfile_default,