Fix build with -no-feature-library

Disable code that directly interacts with QPluginLoader or relies on
QCoreApplication::libraryPaths(). For loading plugins from inside Qt
code you can use QFactoryLoader. If QPluginLoader is necessary, please
consider staticPlugins() and staticInstances().

Change-Id: I14e2e2b5437ddd74109a94cc47dd53f4459ea2f5
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>

src/feedback/qfeedbackplugin.cpp

@@ -120,13 +120,18 @@ class BackendLoader
 {
 public:
     BackendLoader() : inst(0) { }
-    ~BackendLoader() { pl.unload(); }
+    ~BackendLoader() {
+#if QT_CONFIG(library)
+        pl.unload();
+#endif
+    }
 
     void setInstance(T *newInst) { inst = newInst; }
     T * instance() { return inst; }
 
     void tryLoad(QPluginLoader &loader)
     {
+#if QT_CONFIG(library)
         if (T *newInst = qobject_cast<T*>(loader.instance())) {
             if (!inst || inst->pluginPriority() < newInst->pluginPriority()) {
                 inst = newInst;
@@ -135,6 +140,9 @@ public:
                 pl.load(); //Adds a ref to the library
             }
         }
+#else
+        Q_UNUSED(loader)
+#endif
     }
 
 
@@ -252,6 +260,7 @@ class BackendManager
 public:
     BackendManager()
     {
+#if QT_CONFIG(library)
         QStringList pluginPaths = getPluginPaths(QLatin1String("feedback"));
 
         foreach (const QString& pluginPath, pluginPaths) {
@@ -266,6 +275,7 @@ public:
                 loader.unload();
             }
         }
+#endif
 
         if (!hapticsBackend.instance())
             hapticsBackend.setInstance(new QDummyBackend);

src/feedback/qfeedbackpluginsearch.h

@@ -47,6 +47,7 @@ QT_BEGIN_NAMESPACE
 
 inline QStringList getPluginPaths(const QString& plugintype)
 {
+#if QT_CONFIG(library)
 #if !defined QT_NO_DEBUG
     const bool showDebug = qgetenv("QT_DEBUG_PLUGINS").toInt() > 0;
 #endif
@@ -106,6 +107,10 @@ inline QStringList getPluginPaths(const QString& plugintype)
     }
 
   return  plugins;
+#else
+    Q_UNUSED(plugintype)
+    return QStringList();
+#endif
 }
 
 QT_END_NAMESPACE