[cairo] Win32 thread-safety

[cu]

I also found this to be the case, and all our text output code is
currently wrapped in mutexes.

So I'd be very interested in a fix as well. FWIW I recall having
problems with that code on OSX as well as on Windows, though on Windows
they seem to be more widely spread and more obvious. Incidentally, it
has gotten slightly worse in versions after 1.8.6 (occasionally I try to
disable mutexes and see if the issue was somehow resolved).




Sven Goericke wrote:
> So i tried a "simple" approach and add a global Mutex to my plugin and 
> cover every text-related stuff in my code by this Mutex. And surprise 
> surprise, this helps. But also reduces Performance a bit in the 
> Application, saying X-Plane.
>
> I also don't longer use "normal" Win32-Font objects and 
> "set_font_size()" but switched to Win32ScaledFont (which didn't solve 
> the problem).
>