setting -fdebug-prefix-map via envvar

[Bill Allombert]

On Thu, Jun 25, 2020 at 05:27:42PM -0700, Vagrant Cascadian wrote:
> On 2020-06-26, Bill Allombert wrote:
> > Is it possible to set -fdebug-prefix-map via an environment variable or
> > a similar mechanism rather than through the command line ?
> >
> > The issue is that adding -fdebug-prefix-map=PREFIX to CFLAGS
> > leads to PREFIX leaking in buildlogs and in generated Makefiles and 
> > similar files that can end up inside packages, making previously
> > reproducible packages unreproducible.
> 
> We had proposed BUILD_PATH_PREFIX_MAP to address exactly these kinds of
> issues:
> 
>   https://reproducible-builds.org/specs/build-path-prefix-map/
> 
> Unfortunately it was not accepted into upstream GCC as they did not like
> accepting input from an environment variable (yes, they let
> SOURCE_DATE_EPOCH slip though!) ... not sure if many or any other
> compilers have adopted it.

It is true that using envvar require tools like ccache to be patched to
take them into account.

Cheers,
-- 
Bill. <ballombe at debian.org>

Imagine a large red swirl here.