[PATCH] stdio: Remove memory leak from multibyte convertion (BZ#25691)

[Florian Weimer]

* Adhemerval Zanella via Libc-alpha:

> Both default and wide printf functions might leak memory when
> manipulate multibyte characters conversion depending of the size
> of the input (whether __libc_use_alloca trigger or not the fallback
> heap allocation).
>
> This patch fixes it by issuing the required memory free operation
> and also change the alloca/malloc strategy to a scratch buffer.
>
> The testcase uses input argument size that trigger memory leaks
> on unpatched code, using a scratch buffer the threashold to use
> heap allocation is lower.

Should we remove the malloc altogether?

I think we already have patches for that.