[gtk/gtk-2-24] GDK W32: Ignore autorepeated key presses on modifier keys

[LRN <ruslanizhb src gnome org>]

commit 61162225f712df648f38fd12bc0817cfa9f79a64
Author: Jeremy Tan <jtanx outlook com>
Date:   Sat Sep 17 20:46:30 2016 +0800

    GDK W32: Ignore autorepeated key presses on modifier keys
    
    The X11 backend does not send autorepeated messages for modifier keys,
    and doing so prevents motion compression from working.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=771568

 gdk/win32/gdkevents-win32.c | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/gdk/win32/gdkevents-win32.c b/gdk/win32/gdkevents-win32.c
index e52f21c52e..ac91fa64cb 100644
--- a/gdk/win32/gdkevents-win32.c
+++ b/gdk/win32/gdkevents-win32.c
@@ -2274,6 +2274,14 @@ gdk_event_translate (MSG  *msg,
          in_ime_composition)
        break;
 
+      /* Ignore autorepeats on modifiers */
+      if (msg->message == WM_KEYDOWN &&
+          (msg->wParam == VK_MENU ||
+           msg->wParam == VK_CONTROL ||
+           msg->wParam == VK_SHIFT) &&
+           ((HIWORD(msg->lParam) & KF_REPEAT) >= 1))
+        break;
+
       if (!propagate (&window, msg,
                      _gdk_display->keyboard_grab.window,
                      _gdk_display->keyboard_grab.owner_events,