[PATCH] malloc: Remove malloc_get_state, malloc_set_state

[Paul Eggert]

Thanks for doing all this. Some comments:

> +* The __malloc_get_state and __malloc_set_state functions have been removed
> +  from the API.  __malloc_get_state has been replaced with a stub
> +  implementation.  Existing undumped Emacs binaries will have to be
> +  recompiled so that they do not use glibc malloc (or malloc heap dumping).
> +  Existing installed Emacs binaries (after dumping) are not affected by this
> +  change.

The NEWS item should talk about the public API and so should refer to names 
without leading underscores, and it'd be helpful to have a clearer discussion 
about the backwards-compatibility constraints. Perhaps wording like the 
following instead?

-----
The malloc_get_state and malloc_set_state functions have been removed. 
Already-existing binaries that dynamically link to these functions will get a 
hidden implementation in which malloc_get_state is a stub.  As far as we know, 
these functions are used only by GNU Emacs and this change will not adversely 
affect already-built Emacs executables.  Any undumped Emacs executables, which 
normally exist only during an Emacs build, should be rebuilt by re-running 
'configure; make' in the Emacs build tree.
-----


> +attribute_compat_text_section
> +malloc_get_state (void)
>   {
> ...
> +  return NULL;
>   }

Perhaps __malloc_get_state should set errno to ENOSYS?  Emacs won't care about 
errno, so this would merely be insurance in case someone else does care.

Perhaps the test program should be retained and should check that the hidden 
__malloc_get_state function indeed returns NULL?  Dunno how you'd test 
__malloc_set_state....