hw/xwin: Handle the virtual key code generated by the Fn key on IBM Lenovo laptops

Apparently, IBM Leonovo laptops can generate a key-press event for the Fn
key, with virtual key code 0xFF and scan code extended 0x63

Handle this specially, rather than just passing on key code 0x63 (delete),
so you don't delete what you just typed when you adjust the screen brightness,
etc. :-)

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Colin Harrison <colin.harrison@virgin.net>

hw/xwin/winkeybd.h

@@ -35,6 +35,8 @@
  */
 #include "winkeynames.h"
 
+#define VK_FN 0xFF
+
 #define		WIN_KEYMAP_COLS		3
 
 /* Rows 160 through 165 correspond to software-generated codes, which
@@ -298,7 +300,7 @@ g_iKeyMap [] = {
   /* 252 */	0,		0,		0,
   /* 253 */	0,		0,		0,
   /* 254 */	0,		0,		0,
-  /* 255 */	0,		0,		0
+  /* 255 */	VK_FN,		0,		KEY_Fn  /* Most keyboards don't generate a scancode for Fn, but a few do... */
 };
 
 #endif /* WINKEYBD_H */

hw/xwin/winkeynames.h

@@ -144,7 +144,7 @@
 #define KEY_KP_0         /* 0           Insert    0x52  */   82
 #define KEY_KP_Decimal   /* . (Decimal) Delete    0x53  */   83 
 #define KEY_SysReqest    /* SysReqest             0x54  */   84
-                         /* NOTUSED               0x55  */
+#define KEY_Fn           /* Fn                    0x55  */   85
 #define KEY_Less         /* < (Less)   >(Greater) 0x56  */   86
 #define KEY_F11          /* F11                   0x57  */   87
 #define KEY_F12          /* F12                   0x58  */   88