[gtk/gtk-3-24] [Quartz] Fix some compile warnings in gtkclipboard-quartz.c.

[John Ralls <jralls src gnome org>]

commit 93bf85e92ff441ef02979043e90684e0fd7c2dab
Author: John Ralls <jralls ceridwen us>
Date:   Mon Mar 18 13:33:40 2019 -0700

    [Quartz] Fix some compile warnings in gtkclipboard-quartz.c.

 gtk/gtkclipboard-quartz.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
---
diff --git a/gtk/gtkclipboard-quartz.c b/gtk/gtkclipboard-quartz.c
index 75699cccf5..cdf8db0541 100644
--- a/gtk/gtkclipboard-quartz.c
+++ b/gtk/gtkclipboard-quartz.c
@@ -564,8 +564,16 @@ void
 gtk_clipboard_clear (GtkClipboard *clipboard)
 {
   clipboard_unset (clipboard);
-
-  [clipboard->pasteboard declareTypes:nil owner:nil];
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= 1060
+  if (gdk_quartz_osx_version() >= GDK_OSX_SNOW_LEOPARD)
+    [clipboard->pasteboard clearContents];
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+  else
+#endif
+#endif
+#if MAC_OS_X_VERSION_MIN_REQUIRED < 1060
+    [clipboard->pasteboard declareTypes:nil owner:nil];
+#endif
 }
 
 static void
@@ -851,7 +859,6 @@ gtk_clipboard_wait_for_contents (GtkClipboard *clipboard,
 /**
  * gtk_clipboard_wait_for_text:
  * @clipboard:
- * @target:
  *
  * Returns: (nullable):
  */
@@ -899,7 +906,7 @@ gtk_clipboard_wait_for_image (GtkClipboard *clipboard)
  * gtk_clipboard_wait_for_uris:
  * @clipboard:
  *
- * Returns: (nullable) (array zero-terminated=1):
+ * Returns: (nullable) (array zero-terminated=1) (transfer full) (element-type utf8):
  */
 gchar **
 gtk_clipboard_wait_for_uris (GtkClipboard *clipboard)
@@ -1276,6 +1283,8 @@ _gtk_clipboard_store_all (void)
  * gtk_clipboard_get_selection:
  * @clipboard:
  *
+ * Returns: the selection
+ *
  * Since: 3.22
  */
 GdkAtom