y2038: linux: Provide __settimeofday64 implementation

This patch provides new __settimeofday64 explicit 64 bit function for setting
64 bit time in the kernel (by internally calling __clock_settime64).
Moreover, a 32 bit version - __settimeofday has been refactored to internally
use __settimeofday64.

The __settimeofday is now supposed to be used on systems still supporting 32
bit time (__TIMESIZE != 64) - hence the necessary conversion of struct
timeval to 64 bit struct __timespec64.

Internally the settimeofday uses __settimeofday64. This patch is necessary
for having architectures with __WORDSIZE == 32 Y2038 safe.

Build tests:
./src/scripts/build-many-glibcs.py glibcs

Run-time tests:
- Run specific tests on ARM/x86 32bit systems (qemu):
  https://github.com/lmajewski/meta-y2038 and run tests:
  https://github.com/lmajewski/y2038-tests/commits/master

Above tests were performed with Y2038 redirection applied as well as without
to test proper usage of both __settimeofday64 and __settimeofday.

include/time.h

@@ -8,6 +8,7 @@
 # include <time/mktime-internal.h>
 # include <endian.h>
 # include <time-clockid.h>
+# include <sys/time.h>
 
 extern __typeof (strftime_l) __strftime_l;
 libc_hidden_proto (__strftime_l)
@@ -224,6 +225,14 @@ extern int __sched_rr_get_interval64 (pid_t pid, struct __timespec64 *tp);
 libc_hidden_proto (__sched_rr_get_interval64);
 #endif
 
+#if __TIMESIZE == 64
+# define __settimeofday64 __settimeofday
+#else
+extern int __settimeofday64 (const struct __timeval64 *tv,
+                             const struct timezone *tz);
+libc_hidden_proto (__settimeofday64)
+#endif
+
 /* Compute the `struct tm' representation of T,
    offset OFFSET seconds east of UTC,
    and store year, yday, mon, mday, wday, hour, min, sec into *TP.

time/settimeofday.c

@@ -22,7 +22,7 @@
 /* Set the current time of day and timezone information.
    This call is restricted to the super-user.  */
 int
-__settimeofday (const struct timeval *tv, const struct timezone *tz)
+__settimeofday64 (const struct __timeval64 *tv, const struct timezone *tz)
 {
   if (__glibc_unlikely (tz != 0))
     {
@@ -34,11 +34,22 @@ __settimeofday (const struct timeval *tv, const struct timezone *tz)
       return __settimezone (tz);
     }
 
-  struct timespec ts;
-  TIMEVAL_TO_TIMESPEC (tv, &ts);
-  return __clock_settime (CLOCK_REALTIME, &ts);
+  struct __timespec64 ts = timeval64_to_timespec64 (*tv);
+  return __clock_settime64 (CLOCK_REALTIME, &ts);
 }
 
+#if __TIMESIZE != 64
+libc_hidden_def (__settimeofday64)
+
+int
+__settimeofday (const struct timeval *tv, const struct timezone *tz)
+{
+  struct __timeval64 tv64 = valid_timeval_to_timeval64 (*tv);
+
+  return __settimeofday64 (&tv64, tz);
+}
+#endif
+
 #ifdef VERSION_settimeofday
 weak_alias (__settimeofday, __settimeofday_w);
 default_symbol_version (__settimeofday_w, settimeofday, VERSION_settimeofday);