winebuild: Add an "x86_64" flag

[Alexandre Julliard]

Robert Shearman <rob at codeweavers.com> writes:

> Alexandre Julliard wrote:
>>Are there really enough functions that would need this to justify
>>adding a new flag?
>>
>
> Get/SetWindowLongPtr in user32, RtlUnwindEx in ntdll, NdrClientCall3
> in rpcrt4. These are the ones I have noticed so far.

These sound like they would need a win64 flag, they should be
implemented on all 64-bit platforms, not only x86_64. But we can
probably just as well export them on 32-bit too and avoid the flag.

-- 
Alexandre Julliard
julliard at winehq.org