gnu: Build tarballs deterministically.

* gnu/packages/make-bootstrap.scm (tarball-package)[arguments]: Build tarball
  deterministically.
* gnu/packages/admin.scm (isc-dhcp)[arguments]: In 'post-configure' phase,
  create bind.tar.gz deterministically.
* gnu/packages/video.scm (avidemux)[arguments]: In 'repack-ffmpeg' phase,
  create ffmpeg-1.2.1.tar.bz2 deterministically.

gnu/packages/admin.scm

@@ -412,7 +412,11 @@ connection alive.")
                      (for-each patch-shebang
                                (find-files "bind-9.9.5-P1" ".*"))
                      (zero? (system* "tar" "cf" "bind.tar.gz"
-                                     "bind-9.9.5-P1"))))
+                                     "bind-9.9.5-P1"
+                                     ;; avoid non-determinism in the archive
+                                     "--mtime=@0"
+                                     "--owner=root:0"
+                                     "--group=root:0"))))
                  (alist-cons-after
                   'install 'post-install
                   (lambda* (#:key inputs outputs #:allow-other-keys)

gnu/packages/make-bootstrap.scm

@@ -629,7 +629,9 @@ for `sh' in $PATH, and without nscd, and with static NSS modules."
                                               ,(or (%current-target-system)
                                                    (%current-system))
                                               ".tar.xz")
-                               "."))))))))))
+                               "."
+                               ;; avoid non-determinism in the archive
+                               "--mtime=@0" "--owner=root:0" "--group=root:0"))))))))))
 
 (define %bootstrap-binaries-tarball
   ;; A tarball with the statically-linked bootstrap binaries.

gnu/packages/video.scm

@@ -1150,7 +1150,9 @@ for use with HTML5 video.")
            (with-directory-excursion "avidemux_core/ffmpeg_package"
              (substitute* "ffmpeg-1.2.1/configure"
                (("#! /bin/sh") (string-append "#!" (which "bash"))))
-             (system* "tar" "cjf" "ffmpeg-1.2.1.tar.bz2" "ffmpeg-1.2.1")
+             (system* "tar" "cjf" "ffmpeg-1.2.1.tar.bz2" "ffmpeg-1.2.1"
+                      ;; avoid non-determinism in the archive
+                      "--mtime=@0" "--owner=root:0" "--group=root:0")
              (delete-file-recursively "ffmpeg-1.2.1")))
          (alist-replace 'configure
           (lambda _