bug#20314: [PATCH] Make output of mdate-sh deterministic

Paul Eggert eggert at cs.ucla.edu
Fri Sep 22 03:21:25 UTC 2017

Unfortunately that patch to Automake's mdate-sh is not portable, as TZ='UTC' is 
not a portable setting for the TZ environment variable. POSIX says you're 
supposed to use something like TZ='UTC0' instead. Although TZ='UTC' works when 
glibc is used, this is not necessarily true on other POSIX platforms.

I noticed this problem when recent Automake changes were merged into Gnulib, and 
installed the attached patch to the Automake master branch to fix this. Please 
review any other patches you may be using for reproducible builds, and fix them 
to use TZ='UTC0' instead of TZ='UTC'. Thanks.

For reference, here's the POSIX spec for TZ:


and look for "TZ".
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-lib-mdate.sh-TZ-Use-portable-setting.patch
Type: text/x-patch
Size: 885 bytes
Desc: not available
URL: <http://lists.alioth.debian.org/pipermail/reproducible-builds/attachments/20170921/c564c55d/attachment.bin>

More information about the Reproducible-builds mailing list