iOS: Provide default launch image for 4-inch devices

Otherwise the application will not scale to the full resolution of
the device. We copy the image into the Xcode project, since it's
internal to our build system and not meant as a template to be
edited by the user.

For 5.3 we need to provide a proper qmake/qbs mechanism to handle
launch images.

Task-number: QTBUG-31431
Change-Id: Ied0b2843a78c5ea865750e0404418ced7ad27082
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>

mkspecs/macx-ios-clang/features/default_post.prf

@@ -173,6 +173,16 @@ macx-xcode {
     ios_device_family.name = TARGETED_DEVICE_FAMILY
     ios_device_family.value = $$QMAKE_IOS_TARGETED_DEVICE_FAMILY
     QMAKE_MAC_XCODE_SETTINGS += ios_device_family
+
+    # Set up default 4-inch iPhone/iPod launch image so that our apps
+    # support the full screen resolution of those devices.
+    launch_image = Default-568h@2x.png
+    copy_image.input = $$QMAKESPEC/$$launch_image
+    copy_image.output = $$OUT_PWD/$${TARGET}.xcodeproj/$$launch_image
+    copy_image.CONFIG = verbatim
+    QMAKE_SUBSTITUTES += copy_image
+    launch_images.files = $$copy_image.output
+    QMAKE_BUNDLE_DATA += launch_images
 }
 
 macx-xcode {