patch 8.0.0522: Win32: when 'clipboard' is "unnamed" yyp does not work

Problem:    MS-Windows: when 'clipboard' is "unnamed" yyp does not work in a
            :global command.
Solution:   When setting the clipboard was postponed, do not clear the
            register.

src/ui.c

@@ -392,8 +392,6 @@ ui_breakcheck_force(int force)
 
 #if defined(FEAT_CLIPBOARD) || defined(PROTO)
 
-static void clip_copy_selection(VimClipboard *clip);
-
 /*
  * Selection stuff using Visual mode, for cutting and pasting text to other
  * windows.
@@ -569,7 +567,8 @@ clip_copy_selection(VimClipboard *clip)
  * considerably.
  */
 static int global_change_count = 0; /* if set, inside a start_global_changes */
-static int clipboard_needs_update; /* clipboard needs to be updated */
+static int clipboard_needs_update = FALSE; /* clipboard needs to be updated */
+static int clip_did_set_selection = TRUE;
 
 /*
  * Save clip_unnamed and reset it.
@@ -589,6 +588,16 @@ start_global_changes(void)
     }
 }
 
+/*
+ * Return TRUE if setting the clipboard was postponed, it already contains the
+ * right text.
+ */
+    int
+is_clipboard_needs_update()
+{
+    return clipboard_needs_update;
+}
+
 /*
  * Restore clip_unnamed and set the selection when needed.
  */
@@ -619,6 +628,7 @@ end_global_changes(void)
 	    }
 	}
     }
+    clipboard_needs_update = FALSE;
 }
 
 /*