[ARM] Add endless loop to avoid a compiler warning on noreturn functions.

[Christophe Lyon]

On Tue, 2 Oct 2018 at 00:25, Craig Howland <howland@lgsinnovations.com> wrote:
>
> On 10/01/2018 05:27 PM, Christophe Lyon wrote:
> > Hi,
> >
> > While building newlib for ARM, I noticed GCC warnings for _exit() that
> > the compiler thinks they return a value despite being noreturn.
> >
> > Like other targets, this small adds an endless loop to avoid the warning.
> >
> > OK?
> >
> > Christophe
> The proper fix (for both places) is to add noreturn to the _kill() prototype in
> the file.  (Which presumably is true, otherwise _exit() will return.  I did test
> that it fixes the warning.)  (It would not be surprising if it also needed to be
> added to the _kill() source, itself.)

Well, when compiled with ARM_RDI_MONITOR, _kill does seem to return:
#if SEMIHOST_V2
if (_has_ext_exit_extended ())
  return do_AngelSWI (insn, block);
else
#endif
  return do_AngelSWI (insn, (void*)block[0]);

I guess the noreturn should not be added to
newlib/libc/include/sys/signal.h
because it depends on the actual target implementation of _kill?

> Craig