Fix -Wempty-body warnings in system-specific code

[Joseph Myers]

On Mon, 18 Feb 2019, Adhemerval Zanella wrote:

> Can't we just use my 'wcsmbs: optimize wcpcpy' [1] instead?
> 
> [1] https://sourceware.org/ml/libc-alpha/2019-02/msg00155.html

That looks like it would also deal with the issue for that file, yes 
(while the hurdinit.c change would still be needed).

-- 
Joseph S. Myers
joseph@codesourcery.com