Re: [RFC] Replacing malloc_get_state functionality.

[Paul Eggert <eggert@cs.ucla.edu>]

'./configure emacs_cv_var_doug_lea_malloc=no' works for me in the sense 
that I can do a 'make bootstrap' on Fedora 20 x86-64, and the resulting 
Emacs works interactively.  In this configuration Emacs supplies its own 
malloc so the performance is not quite as good (text 0.5% larger, data 
7.6% larger, 14% more CPU time on my usual benchmark) but I don't 
observe any bugs.

It's possible that there's a bigger problem here; but if so, wouldn't it 
the same bigger problem exist on non-glibc platforms already?  If so, 
any fix should also work on any future glibc platforms that lack 
malloc_get_state.

More generally, Emacs by itself should not inhibit glibc from making 
significant malloc performance improvements that would benefit a large 
set of programs.  If Emacs is the main reason these improvements aren't 
being made, then we should go ahead and make them, as we should be able 
to tweak Emacs to work well with the resulting system.