emacs-27 1fc9de4: Improve reproducibility of generated -pkg.el files

[Glenn Morris]

branch: emacs-27
commit 1fc9de4b81ceacabef6aafe48ecaabaf76f34bb2
Author: Glenn Morris <rgm@gnu.org>
Commit: Glenn Morris <rgm@gnu.org>

    Improve reproducibility of generated -pkg.el files
    
    * lisp/emacs-lisp/package.el (package-generate-description-file):
    Don't include the full name of the source file in the header,
    since that varies non-reproducibly according to the build directory.
    https://bugs.debian.org/972861
    Note that elpa.gnu.org's admin/archive-contents.el does this by hand
    and already only includes the nondirectory part.
---
 lisp/emacs-lisp/package.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index fc8dfe1..504eb99 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -963,7 +963,8 @@ untar into a directory named DIR; otherwise, signal an 
error."
       (write-region
        (concat
         ";;; Generated package description from "
-        (replace-regexp-in-string "-pkg\\.el\\'" ".el" pkg-file)
+        (replace-regexp-in-string "-pkg\\.el\\'" ".el"
+                                  (file-name-nondirectory pkg-file))
         "  -*- no-byte-compile: t -*-\n"
         (prin1-to-string
          (nconc