Add option to use default symbol visiblity for VTK-m libraries.
VTK doesn't hide symbols for static builds, which results in linker errors for VTK targets that link with VTK-m. This option allows VTK-m to match VTK's behavior.
VTK doesn't hide symbols for static builds, which results in linker errors for VTK targets that link with VTK-m. This option allows VTK-m to match VTK's behavior.