Utils: Collapse most of porting,h

Taking the Qt 6 branches, leaving some dummies until downstream
adapted.

Change-Id: Ib9b86568d73c341c8f740ba497c3cbfab830d8a1
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/libs/utils/filepath.cpp

@@ -1410,7 +1410,7 @@ FilePath FilePath::stringAppended(const QString &str) const
     return fn;
 }
 
-QHashValueType FilePath::hash(uint seed) const
+size_t FilePath::hash(uint seed) const
 {
     if (HostOsInfo::fileNameCaseSensitivity() == Qt::CaseInsensitive)
         return qHash(m_data.toCaseFolded(), seed);