diff --git a/lib/lib.pro b/lib/lib.pro
index 701e7d359db5f6f2d5f3e9b6fae96fd09d6530f6..e9689fa393f5b6df823db25f43b1255fa74128dc 100644
--- a/lib/lib.pro
+++ b/lib/lib.pro
@@ -10,7 +10,8 @@ TEMPLATE = lib
 TARGET = Qt5WebEngineCore
 
 # Defining keywords such as 'signal' clashes with the chromium code base.
-DEFINES += QT_NO_KEYWORDS
+DEFINES += QT_NO_KEYWORDS \
+           Q_FORWARD_DECLARE_OBJC_CLASS=QT_FORWARD_DECLARE_CLASS
 
 # We need a way to tap into gyp´s Debug vs. Release configuration
 PER_CONFIG_DEFINES = QTWEBENGINEPROCESS_PATH=\\\"$$getOutDir()/%config/$$QTWEBENGINEPROCESS_NAME\\\"
diff --git a/shared/shared.pro b/shared/shared.pro
index 3826bb5eda33337054d7b0c6b82f41ec80949008..108a9a255cc91f0b305f39ea0b09ddafda7077ff 100644
--- a/shared/shared.pro
+++ b/shared/shared.pro
@@ -10,7 +10,8 @@ CONFIG += static
 TARGET = qtwebengine_shared
 
 # Defining keywords such as 'signal' clashes with the chromium code base.
-DEFINES += QT_NO_KEYWORDS
+DEFINES += QT_NO_KEYWORDS \
+           Q_FORWARD_DECLARE_OBJC_CLASS=QT_FORWARD_DECLARE_CLASS
 
 # We need a way to tap into gyp´s Debug vs. Release configuration
 PER_CONFIG_DEFINES = QTWEBENGINEPROCESS_PATH=\\\"$$getOutDir()/%config/$$QTWEBENGINEPROCESS_NAME\\\"