properly handle reading/writing utf-8 filenames on Windows
The wrappers to properly convert utf-8 filenames for reading/writing on Windows have not yet been ported.
See Pd Vanilla git: https://sourceforge.net/p/pure-data/pure-data/ci/master/tree/#
commit: 78b81aa3cb903d923da9eec8ad104935a5ae9ce4
plus some other commits after that one