* rdi-share/unixcomm.c: If using cygwin32, also use the SERPORT and
PARPORT defines for win32.
(Unix_MatchValidSerialDevice): For cygwin32, valid serial port names
start with "com", not "/dev/tty".
(Unix_OpenSerial): Do not use O_NONBLOCK on cygwin32.
* rdi-share/devsw.c (DevSW_Close): Free the device's state (SwitcherState)
so that the device may be reopened.
* remote-rdi.c (mywritec): Send all output through gdb's *_unfiltered
functions, ignoring non-ASCII chars, so that non-tty UI's can snarf
the output from fputs_hook.
(mywrite): Ditto.
(arm_rdi_open): Set inferior_pid.
(arm_rdi_detach): Pop the target off the target stack so that
users can attach and detach multiple times.
(arm_rdi_close): Close the opened device and reset inferior_pid, too.
