Add patch to make the documentation build reproducible

Thanks: Chris Lamb
Closes: #1076806

debian/patches/Make-the-documentation-reproducible-when-rebuilt.patch

+From: Chris Lamb <lamby@debian.org>
+Date: Tue, 23 Jul 2024 14:37:05 +0100
+Subject: Make the documentation reproducible when rebuilt
+
+The Reproducible Builds project aims to arrange for rebuilding the same
+source code in a sufficiently similar environment to produce the same
+installable packages every time, as a way to discourage supply-chain
+attacks by making it possible to verify that a particular installable
+package was built from the claimed source code.
+
+Previously, if meson-python was built twice, at least a year apart,
+then its documentation would contain different copyright dates. The
+SOURCE_DATE_EPOCH environment variable is used here to avoid that
+difference: the intention is that environments that want to produce
+reproducible packages will set SOURCE_DATE_EPOCH to some suitable fixed
+date (perhaps the date of the most recent git commit) which is held
+constant across rebuilds.
+
+See the specification for SOURCE_DATE_EPOCH for more details:
+https://reproducible-builds.org/docs/source-date-epoch/
+
+[smcv: Added commit message]
+
+Co-authored-by: Simon McVittie <smcv@debian.org>
+Bug-Debian: https://bugs.debian.org/1076806
+Forwarded: https://github.com/mesonbuild/meson-python/pull/652
+---
+ docs/conf.py | 8 +++++++-
+ 1 file changed, 7 insertions(+), 1 deletion(-)
+
+diff --git a/docs/conf.py b/docs/conf.py
+index d191a89..5f39f0e 100644
+--- a/docs/conf.py
++++ b/docs/conf.py
+@@ -16,15 +16,21 @@
+ 
+ import datetime
+ import os
++import time
+ import sys
+ sys.path.insert(0, os.path.abspath('..'))
+ import mesonpy
+ 
++build_date = datetime.datetime.fromtimestamp(
++    int(os.environ.get('SOURCE_DATE_EPOCH', time.time())),
++    tz=datetime.timezone.utc,
++)
++
+ 
+ # -- Project information -----------------------------------------------------
+ 
+ project = 'meson-python'
+-copyright = f'2021\N{EN DASH}{datetime.date.today().year} The meson-python developers'
++copyright = f'2021\N{EN DASH}{build_date.year} The meson-python developers'
+ 
+ # The short X.Y version
+ version = mesonpy.__version__

debian/patches/series

 TST-adapt-to-changes-in-pyproject-metadata-0.8.0.patch
+Make-the-documentation-reproducible-when-rebuilt.patch