backport few fixes in paraview/release
- missing some include in vtkStructuredData and ERFReader: !11276 (merged)
- Fix for min,max macros conflicting with VTK headers : !11279 (merged)
- fixups for utf-8 support on Windows : !11274 (merged)
- Python char conversion enforces string length of 1 : !10684 (merged)
- Fix polyhedron IsConvex : !11273 (merged)
Edited by Mathieu Westphal (Kitware)