(sys_kill): Set extended key flag when faking

(sys_kill): Set extended key flag when faking
Ctrl-Break keystrokes.
(Fw32_get_locale_info): Allow LONGFORM parameter to specify an
arbitrary locale property using a numerical index.
(Vw32_valid_codepages): New variable.
(enum_codepage_fn):
(Fw32_get_valid_codepages):
(Fw32_get_console_codepage):
(Fw32_set_console_codepage):
(Fw32_get_console_output_codepage):
(Fw32_set_console_output_codepage):
(Fw32_get_codepage_charset):
(Fw32_get_valid_keyboard_layouts):
(Fw32_get_keyboard_layout):
(Fw32_set_keyboard_layout): New functions, exposing Windows locale
handling functions.
(syms_of_ntproc): Register them.