Fix bug #14970 with crashes when deleting many frames on MS-Windows.

 src/w32fns.c (w32_wnd_proc) <WM_IME_STARTCOMPOSITION>: Make sure the
 frame which got the message is still alive, before dereferencing
 its pointer.
 src/frame.c (delete_frame): Test "this" frame's minibuffer window to
 be a live window, before using it as such.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/w32fns.c b/src/w32fns.c
index 675b716f3b0..2b06936d119 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -3213,6 +3213,8 @@ w32_wnd_proc (HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
              described by W was deleted, as indicated by its buffer
              field being reset to nil.  */
           f = x_window_to_frame (dpyinfo, hwnd);
+          if (!(f && FRAME_LIVE_P (f)))
+            break;
           w = XWINDOW (FRAME_SELECTED_WINDOW (f));
           /* Punt if someone changed the frame's selected window
              behind our back. */