[Reproducible-builds] [PATCH] Make output of mdate-sh deterministic

[Reiner Herrmann]

mdate-sh pretty-prints the modification time of a file.
But it's output can vary depending on the timezone of
the caller. Someone in timezone GMT-12 will get a different
result (day) than someone in timezone GMT+12.

As this output is also used to create/update stamp files,
which influence the further build process, the build result
can vary.
To enable reproducible builds and to have a more deterministic
build behavior, this change fixes the timezone to UTC.

Signed-off-by: Reiner Herrmann <reiner at reiner-h.de>
---
 lib/mdate-sh | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/mdate-sh b/lib/mdate-sh
index b793600..3e7d6ae 100755
--- a/lib/mdate-sh
+++ b/lib/mdate-sh
@@ -1,7 +1,7 @@
 #!/bin/sh
 # Get modification time of a file or directory and pretty-print it.
 
-scriptversion=2010-08-21.06; # UTC
+scriptversion=2015-04-09.19; # UTC
 
 # Copyright (C) 1995-2015 Free Software Foundation, Inc.
 # written by Ulrich Drepper <drepper at gnu.ai.mit.edu>, June 1995
@@ -74,6 +74,10 @@ export LC_ALL
 LC_TIME=C
 export LC_TIME
 
+# Use UTC to get reproducible result
+TZ=UTC
+export TZ
+
 # GNU ls changes its time format in response to the TIME_STYLE
 # variable.  Since we cannot assume 'unset' works, revert this
 # variable to its documented default.
-- 
2.1.4