(putchar): Call internal_flush instead of _flsbuf.

(putchar): Call internal_flush instead of _flsbuf.
(DO_TERMSCRIPT): New macro to support open-termscript.
(internal_flush): Corrected handling of flush in middle of
escape sequences. Handle screen width > 127.
(flush_escape): New function for use by internal_flush.
(sys_select): New MS-DOS specific version with us timing.
(EMACSCOLORS): New environment variable.
(IT_clear_end_of_line): Set default face.
(run_msdos_command): Restore mouse position after command.
Close "backup fd"s.
Corrected switch to cooked mode while running command.
(mouse_on, mouse_off): Now checks have_mouse > 0.
Note: "have_mouse < 0" means that a mouse is present, but
it has been disabled via msdos-mouse-disable.
(IT_write_glyphs): Allow esc-character itself to be printed.
(event_timestamp): New function to make reliable times stamps.
(sys_chdir): Skip drive letter before calling chdir.
(sleep_or_kbd_hit): Handle 60 seconds time wrap.
(mouse_get_pos): Return event_timestamp.