App: correctly handle UTF-8 encoded path names under Windows

src/App/Document.cpp

@@ -2613,7 +2613,12 @@ bool Document::saveToFile(const char* filename) const
     }
     Base::FileInfo tmp(fn);
     // In case some folders in the path do not exist
+#ifdef FC_OS_WIN32
+    QString utf8Name = QString::fromUtf8(filename);
+    auto parentPath = fs::absolute(fs::path(utf8Name.toStdWString())).parent_path();
+#else
     auto parentPath = fs::absolute(fs::path(filename)).parent_path();
+#endif
     fs::create_directories(parentPath);
 
     // open extra scope to close ZipWriter properly