Fix build with Qt 6

Change-Id: I5c775460563dde17a363ea875d7f993e4e4d6ecd
Reviewed-by: Leander Schulten <Leander.Schulten@rwth-aachen.de>
Reviewed-by: Marco Bubke <marco.bubke@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/debugger/gdb/gdbengine.cpp

@@ -3168,7 +3168,7 @@ void GdbEngine::handleRegisterListing(const DebuggerResponse &response)
         reg.name = parts.at(0);
         reg.size = parts.at(4).toInt();
         reg.reportedType = parts.at(5);
-        reg.groups = parts.at(6).split(',').toSet();
+        reg.groups = Utils::toSet(parts.at(6).split(','));
         m_registers[gdbRegisterNumber] = reg;
     }
 }

src/plugins/qmldesigner/designercore/imagecache/imagecachecollectorinterface.h

@@ -28,6 +28,7 @@
 #include <imagecacheauxiliarydata.h>
 #include <utils/smallstringview.h>
 
+#include <QIcon>
 #include <QImage>
 
 namespace QmlDesigner {

src/plugins/qmldesigner/designercore/include/synchronousimagecache.h

@@ -29,6 +29,7 @@
 
 #include <utils/smallstring.h>
 
+#include <QIcon>
 #include <QImage>
 
 #include <condition_variable>