support: Add support_path_support_time64_value

It allows to check for support on arbitrary timestamp values.

support/support.h

@@ -130,9 +130,16 @@ extern void support_copy_file (const char *from, const char *to);
 extern ssize_t support_copy_file_range (int, off64_t *, int, off64_t *,
 					size_t, unsigned int);
 
-/* Return true is PATH supports 64-bit time_t interfaces for file
+/* Return true if PATH supports 64-bit time_t interfaces for file
    operations (such as fstatat or utimensat).  */
-extern bool support_path_support_time64 (const char *path);
+extern bool support_path_support_time64_value (const char *path, int64_t at,
+					       int64_t mt);
+static __inline bool support_path_support_time64 (const char *path)
+{
+  /* 1s and 2s after y2038 limit.  */
+  return support_path_support_time64_value (path, 0x80000001ULL,
+					    0x80000002ULL);
+}
 
 /* Return true if stat supports nanoseconds resolution.  */
 extern bool support_stat_nanoseconds (void);

support/support_path_support_time64.c

@@ -36,19 +36,15 @@ utimesat_call (const char *path, const struct __timespec64 tsp[2])
 #endif
 
 bool
-support_path_support_time64 (const char *path)
+support_path_support_time64_value (const char *path, int64_t at, int64_t mt)
 {
 #ifdef __linux__
   /* Obtain the original timestamps to restore at the end.  */
   struct statx ostx;
   TEST_VERIFY_EXIT (statx (AT_FDCWD, path, 0, STATX_BASIC_STATS, &ostx) == 0);
 
-  const struct __timespec64 tsp[] =
+  const struct __timespec64 tsp[] = { { at, 0 }, { mt, 0 } };
-  {
+
-    /* 1s and 2s after y2038 limit.  */
-    { 0x80000001ULL, 0 },
-    { 0x80000002ULL, 0 }
-  };
   /* Return is kernel does not support __NR_utimensat_time64.  */
   if (utimesat_call (path, tsp) == -1)
     return false;