* ser-mingw.c: Include <conio.h>.
(struct ser_console_state, struct net_windows_state): Add exit_select,
have_stopped, thread.
(pipe_select_thread, console_select_thread)
(net_windows_select_thread): Don't create a local state copy or
close stop_select. Exit on exit_select instead of stop_select. Set
have_stopped.
(console_select_thread): Don't report control keypresses as pending
input.
(pipe_select_thread): Allow stop_select to interrupt sleeping.
(set_console_wait_handle): Create exit_select and have_stopped.
Save the thread handle. Check _kbhit before starting a thread.
(ser_console_done_wait_handle): New.
(ser_console_close): Close new handles. Wait for the thread to
exit.
(new_windows_select_thread): Assert that an event occurred.
(net_windows_wait_handle): Check for pending input before starting
a thread.
(net_windows_done_wait_handle): New.
(net_windows_open): Create exit_select and have_stopped.
Save the thread handle.
(net_windows_close): Close new handles. Wait for the thread to
exit.
(_intiialize_ser_windows): Register done_wait_handle methods.
* serial.c [USE_WIN32API] (serial_done_wait_handle): New.
* serial.h [USE_WIN32API] (struct serial_ops): Add done_wait_handle.
[USE_WIN32API] (serial_done_wait_handle): New prototype.
* mingw-hdep.c (gdb_select): Use serial_done_wait_handle.