Robbie Li authored Jul 19, 2017 and Brad King committed Oct 25, 2017

On Windows, the vtksys::SystemTools::Fopen() function uses the cmake
KWSYS_ENCODING_DEFAULT_CODEPAGE setting for the encoding of filenames.
After this change, people can build VTK libraries that use utf8
filenames by setting KWSYS_ENCODING_DEFAULT_CODEPAGE=CP_UTF8.