* win32-nat.c (DR6_CLEAR_VALUE): New define.

	* win32-nat.c (DR6_CLEAR_VALUE): New define.
	(thread_info_struct): Rename suspend_count to suspended, to be
	used as a flag.
	(thread_rec): Only suspend the thread if it wasn't suspended by
	gdb before.  Warn if suspending failed.
	(win32_add_thread): Set Dr6 to DR6_CLEAR_VALUE.
	(win32_continue): Set Dr6 to DR6_CLEAR_VALUE.  Update usage of the
	`suspended' flag.  Do ContinueDebugEvent after resuming the
	suspended threads, not before.  Set threads' contexts before
	resuming them, not after.
	(win32_resume): Set Dr6 to DR6_CLEAR_VALUE.