time: Fix compile error in itimer test affecting hurd

The recent change to use __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64 to avoid
doing 64-bit checks on some platforms broke the test for hurd where
__KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64 is not defined.  With error:

    tst-itimer.c: In function 'do_test':
    tst-itimer.c:103:11: error: '__KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64' undeclared (first use in this function)
      103 |       if (__KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64)
	  |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    tst-itimer.c:103:11: note: each undeclared identifier is reported only once for each function it appears in

Define a support helper to detect when setitimer and getitimer support
64-bit time_t.

Fixes commit 6e8a0aac2f ("time: Fix overflow itimer tests on 32-bit
systems").

Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: Joseph Myers <joseph@codesourcery.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/support/support.h b/support/support.h
index c219e0d..837a806 100644
--- a/support/support.h
+++ b/support/support.h
@@ -152,6 +152,18 @@ static __inline bool support_path_support_time64 (const char *path)
 					    0x80000002ULL);
 }
 
+/* Return true if the setitimer and getitimer syscalls support 64-bit time_t
+   values without resulting in overflow.  This is not true on some linux systems
+   which have 64-bit time_t due to legacy kernel API's.  */
+static __inline bool support_itimer_support_time64 (void)
+{
+#ifdef __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
+  return __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64;
+#else
+  return sizeof (__time_t) == 8;
+#endif
+}
+
 /* Return true if stat supports nanoseconds resolution.  PATH is used
    for tests and its ctime may change.  */
 extern bool support_stat_nanoseconds (const char *path);