From: =?utf-8?q?Alexis_Bienven=C3=BCe?= <pado@passoire.fr>
Date: Sat, 2 Apr 2016 03:05:43 +0000
Subject: Honour SOURCE_DATE_EPOCH for copyright year

Uses SOURCE_DATE_EPOCH environment variable (if set) to
set the copyright year in documentation, to get reproducible build.
---
diff --git a/docs/conf.py b/docs/conf.py
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -3,6 +3,7 @@
 # For the full list of built-in configuration values, see the documentation:
 # https://www.sphinx-doc.org/en/master/usage/configuration.html
 import itertools
+import os
 from pathlib import Path
 import re
 import sys
@@ -13,7 +14,10 @@
 # -- Project information -----------------------------------------------------
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
 
-YEAR = datetime.date.today().strftime("%Y")
+if os.environ['SOURCE_DATE_EPOCH']:
+    YEAR = datetime.datetime.utcfromtimestamp(float(os.environ.get('SOURCE_DATE_EPOCH'))).strftime('%Y')
+else:
+    YEAR = datetime.date.today().strftime('%Y')
 
 project = 'Cython'
 authors = 'Stefan Behnel, Robert Bradshaw, Dag Sverre Seljebotn, Greg Ewing, William Stein, Gabriel Gellner, et al.'
