gnu: mm-common: Build reproducibly.

* gnu/packages/patches/mm-common-reproducible-tarball.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add patch.
* gnu/packages/gnome.scm (mm-common)[source]: Add patch.

gnu/local.mk

@@ -1514,6 +1514,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/mit-krb5-hurd.patch			\
   %D%/packages/patches/mixxx-link-qtscriptbytearray-qtscript.patch	\
   %D%/packages/patches/mixxx-system-googletest-benchmark.patch	\
+  %D%/packages/patches/mm-common-reproducible-tarball.patch	\
   %D%/packages/patches/mpc123-initialize-ao.patch		\
   %D%/packages/patches/mpg321-CVE-2019-14247.patch		\
   %D%/packages/patches/mpg321-gcc-10.patch			\

gnu/packages/gnome.scm

@@ -1141,7 +1141,10 @@ freedesktop.org desktop notification specification.")
                                   "mm-common-" version ".tar.xz"))
               (sha256
                (base32
-                "1x8yvjy0yg17qyhmqws8xh2k8dvzrhpwqz7j1cfwzalrb1i9c5g8"))))
+                "1x8yvjy0yg17qyhmqws8xh2k8dvzrhpwqz7j1cfwzalrb1i9c5g8"))
+              (patches
+               (search-patches
+                "mm-common-reproducible-tarball.patch"))))
     (build-system meson-build-system)
     (arguments
      `(#:phases

gnu/packages/patches/mm-common-reproducible-tarball.patch

@@ -0,0 +1,40 @@
+From 024c121c844a4ec920133eb3f7e6b6ee8044c0b6 Mon Sep 17 00:00:00 2001
+From: Vagrant Cascadian <vagrant@reproducible-builds.org>
+Date: Sat, 12 Dec 2020 04:05:56 +0000
+Original-Patch: https://bugs.debian.org/977177
+Subject: [PATCH] Set uid, username, gid, and group name on files in
+ generated tarball.
+
+The user and group may otherwise vary between builds on different systems.
+
+---
+ util/meson_aux/skeletonmm-tarball.py | 16 +++++++++++++++-
+ 1 file changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/util/meson_aux/skeletonmm-tarball.py b/util/meson_aux/skeletonmm-tarball.py
+index db9e650..89049b6 100755
+--- a/util/meson_aux/skeletonmm-tarball.py
++++ b/util/meson_aux/skeletonmm-tarball.py
+@@ -39,10 +39,18 @@ elif output_file.endswith('.gz'):
+ else:
+   mode = 'w'
+ 
++def reproducible(tarinfo):
++  # Set consistent user and group on files in the tar archive
++  tarinfo.uid = 0
++  tarinfo.uname = 'root'
++  tarinfo.gid = 0
++  tarinfo.gname = 'root'
++  return tarinfo
++
+ with tarfile.open(output_file, mode=mode) as tar_file:
+   os.chdir(source_dir) # Input filenames are relative to source_dir.
+   for file in sys.argv[3:]:
+-    tar_file.add(file)
++    tar_file.add(file, filter=reproducible)
+ # Errors raise exceptions. If an exception is raised, Meson+ninja will notice
+ # that the command failed, despite exit(0).
+ sys.exit(0)
+-- 
+2.29.2
+