[Reproducible-builds] Best approach to strip timestamp in postscript files

[Alexis Bienvenüe]

Hi.

Looking at reproducibility issues in the kannel package, I saw that some
PNG files are converted to PS and then included in another PS file. The
PNG->PS conversion uses 'convert', which adds 'CreationDate' tags to the
result. I don't know what is the best approach to solve this issue, but
considered the following ones:

0) patch the kannel package to remove these tags from the PS files after
PNG->PS conversion with a perl line (I made this in [1]).

1) patch the 'convert' code to remove CreationDate tags from PS output.
But maybe some code somewhere relies on this tag to work?

2) add an option to the convert command to remove CreationDate tags from
PS output, and add this option to the 'convert' calls in kannel build.

3) adds some code to strip-nondeterminism to remove all lines starting
from "%%CreationDate:" from PS files

Note that 1) and 2) may require to do the same for graphicsmagick, as
imagemagick can be replaced by graphicsmagick-imagemagick-compat?

Could you tell me if you think it could be helpful if I work on one of
these approaches? Or maybe some current work is already going to solve
this issue?

Thanks,
Alexis Bienvenüe.

[1] http://docs.passoire.fr/alexis/debian/kannel_1.4.4-2_reproducible.diff