[vtkusers] process.h conflict with windows header

[Ben Boeckel]

On Sun, Jan 14, 2018 at 23:23:47 -0700, jackyko1991 wrote:
> Hi I am trying to write a multithreaded program with boost::asio
> 
> the boost::asio library is calling process.h to find _beginthreadex function
> from the header file, this is ok when using vtk 7 or older versions.
> 
> When I upgrade to vtk 8, the process.h direct to vtk process.h instead of
> windows own c++ header, this confuse the boost library and cannot find the
> suitable built in function.

What header is this? VTK prefixes all of its include files with `vtk`.
I'm not seeing one by that name in the source tree at least.

--Ben