5 files changed, 18 insertions, 9 deletions
diff --git a/src/gui/configure.json b/src/gui/configure.json
index 5163045343..91e6bebc7f 100644
--- a/src/gui/configure.json
+++ b/src/gui/configure.json
@@ -164,7 +164,9 @@
                 { "libs": "-llibpng", "condition": "config.msvc" },
                 { "libs": "-lpng", "condition": "!config.msvc" }
             ],
-            "use": "zlib"
+            "use": [
+                { "lib": "zlib", "condition": "features.system-zlib" }
+            ]
         },
         "mirclient": {
             "label": "Mir client libraries",
@@ -703,6 +705,7 @@
             "label": "  Using system libpng",
             "disable": "input.libpng == 'qt'",
             "enable": "input.libpng == 'system'",
+            "autoDetect": "features.system-zlib",
             "condition": "features.png && libs.libpng",
             "output": [ "privateFeature" ]
         },
diff --git a/src/gui/image/qxbmhandler.cpp b/src/gui/image/qxbmhandler.cpp
index 19015c5dcd..155a4f88b4 100644
--- a/src/gui/image/qxbmhandler.cpp
+++ b/src/gui/image/qxbmhandler.cpp
@@ -143,6 +143,8 @@ static bool read_xbm_body(QIODevice *device, int w, int h, QImage *outImage)
             return false;
     }
 
+    outImage->fill(Qt::color0);       // in case the image data does not cover the full image
+
     outImage->setColorCount(2);
     outImage->setColor(0, qRgb(255,255,255));        // white
     outImage->setColor(1, qRgb(0,0,0));                // black
diff --git a/src/gui/kernel/qguivariant.cpp b/src/gui/kernel/qguivariant.cpp
index bde0d20ea8..090217187e 100644
--- a/src/gui/kernel/qguivariant.cpp
+++ b/src/gui/kernel/qguivariant.cpp
@@ -291,6 +291,7 @@ static bool convert(const QVariant::Private *d, int t,
         default:
             break;
         }
+        break;
     }
 #endif
 #ifndef QT_NO_ICON
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 8471102aee..3f5f71002b 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -2735,26 +2735,29 @@ void QWindowPrivate::setCursor(const QCursor *newCursor)
         cursor = QCursor(Qt::ArrowCursor);
         hasCursor = false;
     }
-    // Only attempt to set cursor and emit signal if there is an actual platform cursor
-    QScreen* screen = q->screen();
-    if (screen && screen->handle()->cursor()) {
-        applyCursor();
+    // Only attempt to emit signal if there is an actual platform cursor
+    if (applyCursor()) {
         QEvent event(QEvent::CursorChange);
         QGuiApplication::sendEvent(q, &event);
     }
 }
 
-void QWindowPrivate::applyCursor()
+// Apply the cursor and returns true iff the platform cursor exists
+bool QWindowPrivate::applyCursor()
 {
     Q_Q(QWindow);
-    if (platformWindow) {
-        if (QPlatformCursor *platformCursor = q->screen()->handle()->cursor()) {
+    if (QScreen *screen = q->screen()) {
+        if (QPlatformCursor *platformCursor = screen->handle()->cursor()) {
+            if (!platformWindow)
+                return true;
             QCursor *c = QGuiApplication::overrideCursor();
             if (!c && hasCursor)
                 c = &cursor;
             platformCursor->changeCursor(c, q);
+            return true;
         }
     }
+    return false;
 }
 #endif // QT_NO_CURSOR
 
diff --git a/src/gui/kernel/qwindow_p.h b/src/gui/kernel/qwindow_p.h
index e8d5830eee..cffe5b4125 100644
--- a/src/gui/kernel/qwindow_p.h
+++ b/src/gui/kernel/qwindow_p.h
@@ -121,7 +121,7 @@ public:
     void maybeQuitOnLastWindowClosed();
 #ifndef QT_NO_CURSOR
     void setCursor(const QCursor *c = 0);
-    void applyCursor();
+    bool applyCursor();
 #endif
 
     void deliverUpdateRequest();