(Vw32_pass_optional_keys_to_system): Variable removed.

(Vw32_pass_optional_keys_to_system): Variable removed.
(Vw32_pass_lwindow_to_system):
(Vw32_pass_rwindow_to_system):
(Vw32_lwindow_modifier):
(Vw32_rwindow_modifier):
(Vw32_apps_modifier):
(Vw32_enable_num_lock):
(Vw32_enable_caps_lock):
(Vw32_scroll_lock_modifier): New variables.
(modifier_set): Return toggle state for Scroll Lock.
(w32_key_to_modifier): New function.  Returns chosen modifier bit
for given key.
(w32_get_modifiers): Returns modifier flags for
non-keyboard input events.
(construct_console_modifiers): Renamed from construct_modifiers;
recognize Windows and Apps keys as modifiers.
(w32_get_key_modifiers): New function.  Returns modifier flags for
keyboard input events.
(map_keypad_keys): Make non-static.  Use second arg as extended
flag.
(w32_grabbed_keys): New variable.
(HOTKEY, HOTKEY_ID, HOTKEY_VK_CODE, HOTKEY_MODIFIERS): New macros.
(register_hot_keys):
(unregister_hot_keys):
(lookup_vk_code):
(w32_parse_hot_key):
(Fw32_register_hot_key):
(Fw32_unregister_hot_key):
(Fw32_registered_hot_keys):
(Fw32_reconstruct_hot_key): New functions to support hotkeys.
(post_character_message): New function.
(w32_msg_pump): Handle new messages for using hotkeys and changing
keyboard layout/language.
(w32_wnd_proc): Major rework of keyboard input handling:
optionally recognize Windows keys and Apps key as modifiers;
optionally treat NumLock, CapsLock and ScrollLock as function
keys; let system translate keystrokes to characters to avoid
system bugs relating to dead-key handling; preserve shift
distinction for control characters; forward keyboard
layout/language changes to lisp; detect and convert hot-key events
to normal keystrokes.
(syms_of_w32fns): Register new functions and variables.
(w32_last_error): New function for use in debugging.