Fix Cygw32 build

* src/pdumper.c (dump_mm_heap_cb_release): Avoid NULL pointer
dereference.
* src/w32dwrite.c (INITGUID) [CYGWIN]: Don't define for Cygwin.
* src/w32menu.c (w32_popup_dialog): Fix Cygw32 build.  (Bug#74312)

1 files changed, 5 insertions, 0 deletions

diff --git a/src/w32menu.c b/src/w32menu.c
index c3d147841b6..b5f87ebb42c 100644
--- a/src/w32menu.c
+++ b/src/w32menu.c
@@ -186,6 +186,11 @@ task_dialog_callback (HWND hwnd, UINT msg, WPARAM wParam,
 Lisp_Object
 w32_popup_dialog (struct frame *f, Lisp_Object header, Lisp_Object contents)
 {
+#ifdef NTGUI_UNICODE
+  typedef int (WINAPI *WideCharToMultiByte_Proc)(UINT,DWORD,LPCWSTR,int,LPSTR,
+                                                 int,LPCSTR,LPBOOL);
+  static MultiByteToWideChar_Proc pMultiByteToWideChar = MultiByteToWideChar;
+#endif /* NTGUI_UNICODE */
   check_window_system (f);
 
   if (task_dialog_indirect)