dbghelp: add EnumerateLoadedModulesEx/EnumerateLoadedModulesExW stubs

[Nikolay Sivov]

On 12.05.2016 0:32, Austin English wrote:
> For https://bugs.winehq.org/show_bug.cgi?id=40614
> 

>  @ stdcall EnumerateLoadedModules(long ptr ptr)
>  @ stdcall EnumerateLoadedModules64(long ptr ptr)
> -@ stub EnumerateLoadedModulesEx
> -@ stub EnumerateLoadedModulesExW
> +@ stdcall EnumerateLoadedModulesEx(ptr ptr ptr)
> +@ stdcall EnumerateLoadedModulesExW(ptr ptr ptr)

For historical reasons first argument is usually made 'long', not that
it matters.

> +BOOL WINAPI EnumerateLoadedModulesExW(HANDLE process,
> +                                      PENUMLOADED_MODULES_CALLBACK64 callback,
> +                                      void *context)

This prototype is wrong.

Are those calls any different from
EnumerateLoadedModulesW64/EnumerateLoadedModules64? It looks like we
could simply forward to existing calls.

Also please update headers.