On high-resolution Retina displays, the OS X window backing store has twice the
pixels as Wine's window backing store.  So, our images get scaled up.  Core
Graphics had been interpolating/smoothing the image, which resulted in
fuzziness.  This tells it not to do that.

I had assumed this wouldn't be necessary since we pass FALSE for the
shouldInterpolate parameter of CGImageCreate() when we create the images.
Apparently, that's not sufficient.

msvcrt: Bump MSVCRT_MB_LEN_MAX to 5 and use it in MSVCRT__wctomb_l for default buffer lengthSet MB_LEN_MAX to 5 to match MSVCRT_MB_LEN_MAX.

The result is compared directly with handle type values like HANDLE_CONTEXT
whose meaningful values are in the high nibble.

When a window is being dragged, we prevent delivery of clicks to Wine.  We were
also preventing telling Wine that a window had been brought forward, but this
was incorrect.  It prevented clicks in the title bar from activating the window.

winemac: Track which window was brought forward by Cocoa separately from the window receiving the click event.

If the mouse is captured, we change which window receives the click event, but
that shouldn't change which window we tell Wine was brought forward by Cocoa.

We can't prevent Cocoa from bringing disabled/no-activate windows forward.  So,
we need to tell Wine about the z-order change.

We still do avoid telling Wine to activate disabled/no-activate windows, though.