(Vwin32_alt_is_meta): Declared.

(win32_kbd_mods_to_emacs): Map Alt to alt_modifier if required.

src/w32inevt.c

@@ -47,6 +47,9 @@ extern void reinvoke_input_signal (void);
 /* from dispnew.c */
 extern int change_frame_size (FRAME_PTR, int, int, int, int);
 
+/* from w32fns.c */
+extern Lisp_Object Vwin32_alt_is_meta;
+
 /* Event queue */
 #define EVENT_QUEUE_SIZE 50
 static INPUT_RECORD event_queue[EVENT_QUEUE_SIZE];
@@ -103,7 +106,7 @@ win32_kbd_mods_to_emacs (DWORD mods)
     mods &= ~ (RIGHT_ALT_PRESSED | LEFT_CTRL_PRESSED);
 
   if (mods & (RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED))
-    retval = meta_modifier;
+    retval = ((NILP (Vwin32_alt_is_meta)) ? alt_modifier : meta_modifier);
   
   if (mods & (RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED))
     {