VPPAPIGEN: use SOURCE_DATE_EPOCH for datestring

bwiedemann@suse.com pointed me that:
For reproducible builds datestring should be generated using
SOURCE_DATE_EPOCH which distributions set centrally, and have build
tools that consume it to produce reproducible output.

https://wiki.debian.org/ReproducibleBuilds/TimestampsProposal#Python

Change-Id: Iefa2b93231bbc4c8af49736be4d7a5720c46b28d
Signed-off-by: Nirmoy Das <nirmoy.aiemd@gmail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/tools/vppapigen/C.py b/src/tools/vppapigen/C.py
index c9e543f486b..b56e0722122 100644
--- a/src/tools/vppapigen/C.py
+++ b/src/tools/vppapigen/C.py
@@ -1,8 +1,9 @@
 # C generation
 import datetime
 import os
+import time
 
-datestring = datetime.datetime.now()
+datestring = datetime.datetime.utcfromtimestamp(int(os.environ.get('SOURCE_DATE_EPOCH', time.time())))
 input_filename = 'inputfil'
 top_boilerplate = '''\
 /*