include[1/2]: add a strcmpW-equivalent function usable in tests.

[Dmitry Timoshkov]

Mikołaj Zalewski <mikolaj at zalewski.pl> wrote:

> +/* strcmpW is avaiable for tests compiled under Wine, but not in standalone
> + * builds under Windows, so we reimplement it under a different name. */
> +static inline int winetest_strcmpW( const WCHAR *str1, const WCHAR *str2 )
> +{
> +    while (*str1 && (*str1 == *str2)) { str1++; str2++; }
> +    return *str1 - *str2;
> +}

'inline' should not be used in Wine tests, and existing 'inline's should be
removed since that's not a valid modifier for MSVC, and we can't include
config.h in tests.

-- 
Dmitry.