gdb/

	gdb/
	* linux-nat.c (kill_lwp): Minor cleanup, move definition of
	tkill_failed into ifdef HAVE_TKILL_SYSCALL.  Move setting of errno
	there too.  Delete unnecessary resetting of errno after syscall.
	Minor comment changes to match gdbserver/linux-low.c:kill_lwp.

	gdbserver/
	* linux-low.c (kill_lwp): Use __NR_tkill instead of SYS_tkill.
	Move definition of tkill_failed to ifdef __NR_tkill to avoid gcc
	warning ifndef __NR_tkill.  Move setting of errno there too.
	Delete unnecessary resetting of errno after syscall.
	Minor comment changes to match gdb/linux-nat.c:kill_lwp.