* inflow.c: Remove unused includes of sys/param.h and sys/types.h.
* inflow.c, ser-unix.c, ser-go32.c, ser-tcp.c, serial.h,
terminal.h, fork-child.c, main.c, utils.c: Move all the process
group stuff back to inflow.c and terminal.h; that's a better place
for it and fixes problems with trying to get/set the process group
of a tty we're doing remote debugging on.
* terminal.h: Skip the redefines and includes if HAVE_TERMIOS.