[ARM, VXworks] Fix build

[Eric Botcazou]

> What I said.  looking at the contents of vxworks.h I see:
> 
> #define CC1_SPEC                                                        \
> "%{tstrongarm:-mlittle-endian -mcpu=strongarm ;                         \
>    t4:        -mlittle-endian -march=armv4 ;                            \
>    t4be:      -mbig-endian -march=armv4 ;                               \
>    t4t:       -mthumb -mthumb-interwork -mlittle-endian -march=armv4t ; \
>    t4tbe:     -mthumb -mthumb-interwork -mbig-endian -march=armv4t ;    \
>    t5:        -mlittle-endian -march=armv5 ;                            \
>    t5be:      -mbig-endian -march=armv5 ;                               \
>    t5t:       -mthumb -mthumb-interwork -mlittle-endian -march=armv5 ;  \
>    t5tbe:     -mthumb -mthumb-interwork -mbig-endian -march=armv5 ;     \
>    txscale:   -mlittle-endian -mcpu=xscale ;                            \
>    txscalebe: -mbig-endian -mcpu=xscale ;                               \
> 
>             : -march=armv4}"
> 
> Nothing in that list post-dates armv5t, and many of the mentioned target
> architectures are under threat of deprecation in GCC, in addition to the
> old ABI (in particular armv5 is a nonsense architecture - it should be
> armv5t).

OK, we have indeed changed the last one locally to -march=armv7-a.

> I also can't see how ARMv7 would work big-endian with the old ABI since
> there's no way of generating BE8 format images without at least some
> features from the new ABI (mapping symbols, forcing --be8 through to the
> linker, etc).  So "works fine" would appear to have quite a narrow
> definition.

Yes, VxWorks certainly doesn't support all the combinations.

> That's good news.  Does that mean we'll be able to drop the old stuff
> though?  I'd really like to make progress towards removing the old ABI
> support from GCC.

Yes, I'd think so, but Olivier knows better.

> Note that considering a port for deprecation is only the first step.  It
> does not mean that it has been deprecated.  Sometimes the only way to
> find out if a port really is wanted is to make such a threat...

No disagreement. ;-)

-- 
Eric Botcazou