[PATCH v2] Remove defines to builtins in string2.h

[Wilco Dijkstra]

Florian Weimer wrote:
> Please remove the definition of _HAVE_STRING_ARCH_strchr as well (from 
> sysdeps/x86/bits/string.h).

Sure I'll have a quick hunt for dead defines. There must be quite a few by now...

> I'm surprised to see stpcpy in this patch because the first paragraph 
> says this change is exclusively about C90 functions, and stpcpy isn't one.

Joseph's reply to my question made it clear the redirection is done elsewhere
in most cases, so that means we can remove the redirections of non-C90
symbols from string2.h as well:

> > Also other headers already ensure (most) non-C90 symbols
> > are redirected to avoid name space clashes.

I checked and there are no namespace issues introduced by my patch
(note strdup/strndup doesn't appear to redirect internally, so building with -Os
or removing the str(n)dup defines from string2.h causes a namespace bug).

Wilco