#10 allow to override build date

[Bernhard M. Wiedemann]

While working on reproducible builds for openSUSE, I found that
our xsnow package varied across builds.

Please apply the attached patch.

extra note: needs --disable-selfrep for bit-identical results or a patch to how tar gets called (tell me, if you are interested)

btw: I created https://github.com/gitmirrors2/xsnow/ and plan to auto-update it from git.

[Willem Vermin]

Thanks for mentioning the issues!

• The SOURCE_DATA_EPOCH thing: I will apply your patch.
• The necessity to use --disable-selfrep: the problem is caused by the time stamps in the
  tar ball created by 'make dist'. I will retar this tarball using the flags --atime-preserve and
  --mtime.

I'll let you know when a new version is available.

Willem

[Bernhard M. Wiedemann]

For the tarball, I got reproducible results with

am__tar='$${TAR-tar} --pax-option=exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime --owner=0 --group=0 --numeric-owner --mtime="@1" --sort=name -chof - "$$tardir"' am__untar='$${TAR-tar} xf -

https://reproducible-builds.org/docs/archives/ has some background on how the parts in there work.

However, half of these options are specific to GNU tar, so if you want to support BSD tar as well, things get more complicated.

[Willem Vermin]

Thanks for the suggestions. I am using something like this

am__tar='$${TAR-tar} --format=posix --pax-option=exthdr.name=%d/PaxHeaders/%f,delete=atime,delete=ctime --owner=0 --group=0 --numeric-owner --mtime="@1" --sort=name -chf - "$$tardir"' 

I get now reproducible builds, except when I use pbuilder to create a debian package. Could you have a look at my attempt (see configure.ac) and test it on your system? You find the new version (3.4.4~pre3) here:
https://www.ratrabbit.nl/ratrabbit/xsnow/downloads/index.html

[Bernhard M. Wiedemann]

I tested your xsnow-3.4.4~pre4.tar.gz and it builds reproducibly in openSUSE. Thanks.

[Willem Vermin]

No message, good message ...
Closing this ticket.