bug#9926: patch: emacs-24.0.91 FTBFS on GNU/Hurd

[Svante Signell]

> I installed the following patch in the trunk as bzr 106311
> to fix the fails-to-compile bug.
> 
> Making GC_MAKE_GCPROS_NOOPS the default sounds good, but as
> it doesn't fix a bug and we're in feature-freeze now I left
> that for later.
> 
> === modified file 'src/ChangeLog'
> --- src/ChangeLog       2011-11-07 02:00:43 +0000
> +++ src/ChangeLog       2011-11-07 05:37:49 +0000
> @@ -1,3 +1,10 @@
> +2011-11-07  Paul Eggert  <address@hidden>
> +
> +       * alloc.c (DEADP): New macro, for porting to GNU/Hurd (Bug#9926).
> +       This is also needed for porting to any host where GC_MARK_STACK is
> +       not GC_MAKE_GCPROS_NOOPS.
> +       (which_symbols): Use it.

Reading your patch shows that GC_MARK_STACK will still not be set for
GNU/Hurd. However, the previous comment by Stefan Monnier says that
GC_MAKE_GCPROS_NOOPS should be set as the default. So what is wrong
with patching gnu.h??

Anyway, which are the differences/consequences of that part of the code
in which_symbols being executed compared to not when GC_MARK_STACK is
unset or set to GC_MAKE_GCPROS_NOOPS?