Replace MPProcessors() to gain improved 64bit compatibility
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
On Mac OS X only some APIs are available to 64 bit applications, see: <http://developer.apple.com/documentation/Darwin/Conceptual/64bitPorting/indications/chapter_2_section_2.html>
Specifically, only the APIs in System.framework and Accelerate.framework are available. So no Carbon, Cocoa, OpenGL, etc.
vtkMultiThreader.cxx is including Carbon to call the function MPProcessors().
This API could be replaced by a different one for 64 bit compatibility.
One option is sysctl() with 'hw.ncpu'-- I think. I'm not 100% sure of the purpose of vtkMultiThreader::GetGlobalDefaultNumberOfThreads().