nixpkgs/pkgs/build-support/emacs/package-build-dont-use-mtime.patch

diff --git a/package-build.el b/package-build.el
index 29cdb61..c19be1b 100644
--- a/package-build.el
+++ b/package-build.el
@@ -923,7 +923,6 @@ DIRECTORY is a temporary directory that contains the directory
 that is put in the tarball."
   (let* ((name (oref rcp name))
          (version (oref rcp version))
-         (time (oref rcp time))
          (tar (expand-file-name (concat name "-" version ".tar")
                                 package-build-archive-dir))
          (dir (concat name "-" version)))
@@ -939,7 +938,7 @@ that is put in the tarball."
        ;; prevent a reproducible tarball as described at
        ;; https://reproducible-builds.org/docs/archives.
        "--sort=name"
-       (format "--mtime=@%d" time)
+       "--mtime=@0"
        "--owner=0" "--group=0" "--numeric-owner"
        "--pax-option=exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime"))
     (when (and package-build-verbose noninteractive)