gzip --no-name: avoid spurious warning

Problem reported by Jim Meyering (Bug#24826).
* tests/timestamp: Add a test from Jim Meyering to exercise the fix
* zip.c (zip): Treat unknown time stamps as 0.

1 files changed, 3 insertions, 1 deletions

diff --git a/zip.c b/zip.c
index eb60409..a3b4559 100644
--- a/zip.c
+++ b/zip.c
@@ -54,7 +54,9 @@ int zip(in, out)
         flags |= ORIG_NAME;
     }
     put_byte(flags);         /* general flags */
-    if (0 < time_stamp.tv_sec && time_stamp.tv_sec <= 0xffffffff)
+    if (time_stamp.tv_nsec < 0)
+      stamp = 0;
+    else if (0 < time_stamp.tv_sec && time_stamp.tv_sec <= 0xffffffff)
       stamp = time_stamp.tv_sec;
     else
       {