Ok, I will do that.

I can eliminate differences in the wrappers easily, then I will look into
the libtool patch.
It seems, that the la files are causing the checksum difference in cc1 and
cc1plus, because if I remove libraries from the checksum, then they agree.
I also checked the same things when I compile with clang. The differences
are the same, so we can do this. The rest is just "cosmetics".


2017-12-02 15:48 GMT+01:00 Jan Nieuwenhuizen <janneke@gnu.org>:

> Gábor Boskovits writes:
>
> > Aside from these libtool files we can now say, that this ddc project
> succeeded.
>
> Wait... The libtool's .la files are now the only files that show any
> difference, even when gcc is compiled into it's own prefix?  That's
> amazing!!!
>
> > I've contacted the libtool developers if we can extend the wrapper
> approach to the .la files.
>
> Great!
>
> > It seems, that in some older version of libtool those were just sourced
> as shell script, but
> > I don't know if now they do something more fancy with it or not...
> > Anyways, if it's just shell script, then the environment variable
> approach can also work out there.
> > The only problem seems, that I should do the substitution before
> checksumming the compiler.
> > I think I can inject something into the makefile, or use a patched
> vesion of libtool.
> >
> > A patched libtool could be a better option, so other ddc projects can
> use it.
>
> Indeed.
>
> > I guess I can do something like add an environment variable
> GUIX_INSTALL_DIRECTORY, or something like that...
>
> What's different about GUIX_INSTALL_DIRECTORY than the usual: PREFIX?
>
> > Any maybe name this version libtool-for-ddc.
> > It should be noted in the package documentation, that this package is
> not recommended for general use.
>
> Are you proposing to patch libtool?  If so, even if patching it for
> [gcc-]dcc only would be a great hack for now.  Please go forward with
> that idea at least until libtool devs help us with a full solution.
>
> janneke
>
> --
> Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
> Freelance IT http://JoyofSource.com | Avatar® http://AvatarAcademy.com
>