[PATCH, d] Disable D on systems where it is known not to work.

[Joseph Myers]

On Wed, 31 Oct 2018, Iain Sandoe wrote:

> maybe if building D .. then libphobos should be automatic 
> (i.e. the opt-in/out for the targets under development is to choose to 
> build/not build D explicitly)?
> 
> [ that would avoid having to have the UNSUPPORTED stuff in the 
> libphobos/config.tgt too .]
> 
> would that be an adequate guard?
> 
> i.e. is there any point to build D FE without also building libphobos?

Well, --enable-languages=all ought to work everywhere, and automatically 
disable (via configure.tgt) libraries that aren't supported.  And building 
front ends for all targets (as done by contrib/config-list.mk, which 
doesn't attempt to build libraries at all) can e.g. show up issues with 
target macro definitions that only result in build failures in some front 
ends.  (This is a use for being able to build it with 
--enable-languages=all for GCC development and testing purposes rather 
than a reason normal users would want that front end.)

I haven't tried build-many-glibcs.py --full-gcc since D support went into 
GCC.  The previous list of failures was 
<https://sourceware.org/ml/libc-alpha/2018-09/msg00110.html> and I expect 
many of the Ada and libgo issues, where not already fixed, wouldn't 
actually be that hard to fix.

-- 
Joseph S. Myers
joseph@codesourcery.com