diff --git a/src/plugins/platformthemes/gtk3/CMakeLists.txt b/src/plugins/platformthemes/gtk3/CMakeLists.txt
index 89acc84f07..c9e4de6124 100644
--- a/src/plugins/platformthemes/gtk3/CMakeLists.txt
+++ b/src/plugins/platformthemes/gtk3/CMakeLists.txt
@@ -23,8 +23,11 @@ qt_internal_add_plugin(QGtk3ThemePlugin
         qgtk3interface.cpp qgtk3interface_p.h
         qgtk3storage.cpp qgtk3storage_p.h
         qgtk3json.cpp qgtk3json_p.h
+    NO_PCH_SOURCES
+        qgtk3dialoghelpers.cpp # undef QT_NO_FOREACH
     DEFINES
         GDK_VERSION_MIN_REQUIRED=GDK_VERSION_3_6
+        QT_NO_FOREACH
     LIBRARIES
         PkgConfig::GTK3
         Qt::Core
diff --git a/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
index b8ba58d30e..08419ec7dc 100644
--- a/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
+++ b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
@@ -1,6 +1,8 @@
 // Copyright (C) 2016 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
+#undef QT_NO_FOREACH // this file contains unported legacy Q_FOREACH uses
+
 #include "qgtk3dialoghelpers.h"
 #include "qgtk3theme.h"