Re-enable QML debugging for debug builds

Make sure 'Enable QML debugging' is checked for all debug builds by
default.

This fixes a regression introduced in 921f86df

.

Task-number: QTCREATORBUG-10573
Change-Id: If3b1e5aedaad888fbaf1931ca2fc379c5ba40dd1
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/qmakeprojectmanager/qmakebuildconfiguration.cpp

@@ -644,7 +644,8 @@ BuildConfiguration *QmakeBuildConfigurationFactory::create(Target *parent, const
             = QmakeBuildConfiguration::removeQMLInspectorFromArguments(&additionalArguments);
     if (!additionalArguments.isEmpty())
         qmakeStep->setUserArguments(additionalArguments);
-    qmakeStep->setLinkQmlDebuggingLibrary(enableQmlDebugger);
+    if (!qmakeInfo->makefile.isEmpty())
+        qmakeStep->setLinkQmlDebuggingLibrary(enableQmlDebugger);
 
     bc->setQMakeBuildConfiguration(config);