[OE-core] [PATCH 0/4] Reproducible binaries

[Bystricky, Juro]

> I wasnted to say "passing the seed value" through some separate variable
> which is easy to override from somewhere else.
> 
> e.g.
> export PRELINK_TIMESTAMP=`git log -1 --pretty=%ct `
> 
> in image-prelink.bbclass:prelink_image() is a bit difficult to override.
> 

I think it is best to keep all reproducible build related variables gathered together, 
so bitbake.conf seems like a natural place (same place as the variable BUILD_REPRODUCIBLE_BINARIES),
i.e something like:

PRELINK_TIMESTAMP ??=`git log -1 --pretty=%ct `

A single "general purpose" fallback timestamp variable (not specific to prelinking) would be my
preference. Unfortunately, the timestamps may need to come in various different formats...