* ser-unix.c (wait_for): Do not reset timeout_remaining for cygwin32 so

    * ser-unix.c (wait_for): Do not reset timeout_remaining for cygwin32 so
that
        we can use this member to track real timeouts.
        (hardwire_readchar): Modify for cygwin32 so that we only ever use a real
        system timeout of one second. Track the "real" timeout as a series of th
ese
        one second timeouts.
        Call ui_loop_hook to keep the gui alive.

        * top.c: Define new hook for cygwin32, "ui_loop_hook".

        * gdbtk.c (gdbtk_init): Add ui_loop_hook for CygWin32 to work around
        update problems.