Change the VTKM_CONT_EXPORT to VTKM_CONT. (Likewise for EXEC and
EXEC_CONT.) Remove the inline from these macros so that they can be
applied to everything, including implementations in a library.
Because inline is not declared in these modifies, you have to add the
keyword to functions and methods where the implementation is not inlined
in the class.
All the other math functions are in the vtkm package. This one was in
vtkm::exec because it uses a callback method. This can be problematic on
CUDA the the declaration of NewtonsMethod does not match the callback
method. However, we now have a VTKM_SUPPRESS_EXEC_WARNINGS macro that
allows a VTKM_EXEC_CONT_EXPORT function (like NewtonsMethod) to call
either a VTKM_EXEC_EXPORT or VTKM_CONT_EXPORT without a warning.
