* src/tar.c (NS_PRECISION_FORMAT_MASK): New macro.

(tar_timespec_cmp): New function. Wrapper over
timespec_cmp using the timespec precision provided by the
current archive format.
* src/common.h (tar_timespec_cmp): New declaration.
* src/compare.c (diff_file): Use tar_timespec_cmp.
* src/extract.c (file_newer_p): Likewise.
* src/update.c (update_archive): Likewise.
* tests/truncate.at: Reverted changes
* tests/update.at: Reverted changes

src/extract.c

@@ -469,7 +469,7 @@ file_newer_p (const char *file_name, struct tar_stat_info *tar_stat)
       return errno != ENOENT;
     }
   if (!S_ISDIR (st.st_mode)
-      && timespec_cmp (tar_stat->mtime, get_stat_mtime (&st)) <= 0)
+      && tar_timespec_cmp (tar_stat->mtime, get_stat_mtime (&st)) <= 0)
     {
       return true;
     }