[Bug target/63773] [meta-bug] Restoring darwin bootstrap for gcc 5.0

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63773

--- Comment #17 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Francois-Xavier Coudert from comment #16)
> (In reply to Iain Sandoe from comment #15)
> > … the second issue - which is that we need a -B…. option for each library
> > path that will be used for spec-substitution (.a for .dylib)
> 
> The necessary -B options are already in POSTSTAGE1_HOST_EXPORTS, through
> POSTSTAGE1_CXX_EXPORT.

excellent.
Jakub asked Paulo on-list if there was a solution to ...

> > I don't think we want to bootstrap libcc1 (that was what the patch was
> > removing).
> > 
> > Probably the right example is gnattools - or something similar that only
> > builds @stage#3.
> 
> I cannot find anything in the top-level Makefile that builds at stage3 and
> uses POSTSTAGE1_HOST_EXPORTS, i.e. properly builds with the final compiler.
> Even gnarls uses HOST_EXPORTS, so it would probably have similar problems.
> (Doesn't it? I don't know cause I never build ada.)

… this ^ i.e. choosing the right one to use depending on
cross/disable-bootstrap/stage#n … 

.. gnattools adds the -B options specifically in its Makefile.

interesting - so that also implies it will be affected by the bootstrap
compiler (although, of course, that pretty much has to be GCC for Ada).  I must
confess I'd not looked beyond the handling of certain configure options.