Cygwin/X: Avoid a visual glitch on window move in rootless modes

Handle and ignore WM_ERASEBKGND since we repaint the entire invalidated region anyhow
(this avoids a white flickering on window resize)

---
 xserver/hw/xwin/winmultiwindowwndproc.c   |    8 ++++++++
 xserver/hw/xwin/winwin32rootlesswndproc.c |   11 +++++++++++
 2 files changed, 19 insertions(+)

Index: xorg-server-1.5.3/xserver/hw/xwin/winmultiwindowwndproc.c
===================================================================
--- xorg-server-1.5.3.orig/xserver/hw/xwin/winmultiwindowwndproc.c	2009-02-10 21:55:54.921875000 +0000
+++ xorg-server-1.5.3/xserver/hw/xwin/winmultiwindowwndproc.c	2009-02-11 14:11:31.343750000 +0000
@@ -468,6 +468,14 @@
       HandleCustomWM_INITMENU ((unsigned long)hwnd, wParam);
       break;
 
+    case WM_ERASEBKGND:
+      /*
+       * Pretend that we did erase the background but we don't care,
+       * since we repaint the entire region anyhow
+       * This avoids some flickering when resizing.
+       */
+      return TRUE;
+
     case WM_PAINT:
       /* Only paint if our window handle is valid */
       if (hwndScreen == NULL)
Index: xorg-server-1.5.3/xserver/hw/xwin/winwin32rootlesswndproc.c
===================================================================
--- xorg-server-1.5.3.orig/xserver/hw/xwin/winwin32rootlesswndproc.c	2009-02-10 21:55:54.656250000 +0000
+++ xorg-server-1.5.3/xserver/hw/xwin/winwin32rootlesswndproc.c	2009-02-10 21:55:56.593750000 +0000
@@ -779,6 +779,17 @@
       SendMessage (hwndScreen, message, wParam, lParam);
       return 0;
 
+    case WM_ERASEBKGND:
+#if CYGDEBUG
+      winDebug ("winMWExtWMWindowProc - WM_ERASEBKGND\n");
+#endif
+      /*
+       * Pretend that we did erase the background but we don't care,
+       * since we repaint the entire region anyhow
+       * This avoids some flickering when resizing.
+       */
+      return TRUE;
+
     case WM_PAINT:
     
       /* BeginPaint gives us an hdc that clips to the invalidated region */