[patch] Fix pr16247

[Rafael Espíndola]

On 10 June 2013 19:08, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> Richard pointed out on IRC that the patch should look at the
> redeclaration context to avoid problems with one of the functions
> being in a extern "C++". Implementing that found some interesting
> problems. Consider
>
> extern "C" {
>   static void foo(int x);
>   static void foo() {
>   }
>   void foo(int x) {
>   }
> }
>
> This should be valid, since both functions have internal linkage and
> therefore none of them has C language linkage. Commenting the first
> declaration makes the code invalid as now the last one is extern C and
> [dcl.link] p6 kicks in. This means we have to do "normal" overload
> resolution first to see if the last decl we are looking at has C
> language linkage or not.

BTW, is this sufficient evidence that we should just give static
functions C language linkage? I just checked http://gcc.godbolt.org/
and gcc 4.8 and icc 13 (which is edg based, no?), reject

extern "C" {
  static void foo() {
  }
  static void foo(int x) {
  }
}

We are putting quiet a bit of effort to make sure we accept it and I
still can't see the value.

Cheers,
Rafael