moc: make qHash(SubArray) accept a seed

This prevents the use of the one-arg-to-two-arg adapter template which
we'd remove rather sooner than later, because it's causing all sorts of
problems, but probably can't, until Qt 7.

Pick-to: 6.6
Task-number: QTBUG-116074
Change-Id: I5907da0dc8c01b636d16dcc01e9c808ab9a85081
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/tools/moc/symbols.h

@@ -7,7 +7,7 @@
 
 #include "token.h"
 #include <qdebug.h>
-#include <qhash.h>
+#include <qhashfunctions.h>
 #include <qlist.h>
 #include <qstack.h>
 #include <qstring.h>
@@ -37,9 +37,9 @@ struct SubArray
     }
 };
 
-inline size_t qHash(const SubArray &key)
+inline size_t qHash(const SubArray &key, size_t seed = 0)
 {
-    return qHash(QLatin1StringView(key.array.constData() + key.from, key.len));
+    return qHash(QLatin1StringView(key.array.constData() + key.from, key.len), seed);
 }