Add missing libraries to Linux build

Add test for an existing window before attempting to close it.

QGCSetup.pri

@@ -110,9 +110,11 @@ LinuxBuild {
         libQt5Gui.so.5 \
         libQt5Location.so.5 \
         libQt5Multimedia.so.5 \
+        libQt5MultimediaQuick.so.5 \
         libQt5Network.so.5 \
         libQt5OpenGL.so.5 \
         libQt5Positioning.so.5 \
+        libQt5PositioningQuick.so.5 \
         libQt5PrintSupport.so.5 \
         libQt5Qml.so.5 \
         libQt5Quick.so.5 \

src/ui/MainWindowHybrid.qml

@@ -22,11 +22,19 @@ Item {
     }
 
     function attemptWindowClose() {
-        mainWindowInner.item.attemptWindowClose()
+        if(!mainWindowInner.item) {
+            controller.reallyClose()
+        } else {
+            mainWindowInner.item.attemptWindowClose()
+        }
     }
 
     function showMessage(message) {
-        mainWindowInner.item.showMessage(message)
+        if(mainWindowInner.item) {
+            mainWindowInner.item.showMessage(message)
+        } else {
+            console.log(message)
+        }
     }
 
     Loader {