Utils: Add toSet/toList functions

As replacement for functionality that's being deprecated
in Qt but still useful or needed, or that cannot easily be handled
without resorting to #if QT_VERSION checks in user code.

Change-Id: Id3575a54ff944bf0e89d452d13944fcaee270208
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/libs/utils/algorithm.h

@@ -1243,4 +1243,27 @@ OutputIterator set_union(InputIterator1 first1,
     return Utils::set_union_impl(
         first1, last1, first2, last2, result, std::less<typename InputIterator1::value_type>{});
 }
+
+// Replacement for deprecated Qt functionality
+
+template <class T>
+QSet<T> toSet(const QList<T> &list)
+{
+#if (QT_VERSION < QT_VERSION_CHECK(5, 13, 0))
+    return list.toSet();
+#else
+    return QSet<T>{list.begin(), list.end()};
+#endif
+}
+
+template <class T>
+QList<T> toList(const QSet<T> &set)
+{
+#if (QT_VERSION < QT_VERSION_CHECK(5, 13, 0))
+    return set.toList();
+#else
+    return QList<T>{set.begin(), set.end()};
+#endif
+}
+
 } // namespace Utils