Trying to add an exit confirmation dialog to Cygwin setup.exe, failing

[Terry Fleming]

--- original/setup-2.573.2.3/propsheet.cc
+++ setup-2.573.2.3/propsheet.cc
@@ -162,6 +162,11 @@
 static LRESULT CALLBACK PropSheetWndProc (HWND hwnd, UINT uMsg,
   WPARAM wParam, LPARAM lParam)
 {
+if(((uMsg==WM_SYSCOMMAND)&&((wParam&0xfff0)==SC_CLOSE))||
+	(((uMsg==WM_COMMAND)&&(wParam==2))))
+		if(MessageBox(hwnd,
+			"Are you sure you want to exit setup? Any current download or
installation will be aborted.",
+			"Exit Cygwin Setup?", MB_YESNO)==IDNO) return 0;
   PropSheetData& psd = PropSheetData::Instance();
   switch (uMsg)
     {