Problem with NSInvocation on Windows

[Roland Schwingel]

Hi...

There is a problem using NSInvocation on windows. It always allocates a 
windows native virtual memory page for it's informations. Depending on 
the windows version such a page can be very big and the number of these 
pages are limited. If you have a lot of NSInvocation instances this 
fragments your memory and you can also run out of virtual pages when you 
are using ffi invocations.

The attached (trivial) patch fixes this. It allocates pages now using 
malloc and later on adjusts the allocated memory flags using 
VirtualProtect().

Thanks for applying,

Roland