* target.h (TARGET_WNOHANG): New.

* target.c (target_wait): Add `options' argument.  Adjust.
	(struct target_ops) <to_wait>: Add `options' argument.
	(target_wait): Add `options' argument.
	* infrun.c (wait_for_inferior): Pass 0 as options to
	target_wait (blocking wait).
	(fetch_inferior_event): Pass TARGET_WNOHANG as options to
	target_wait.
	* fork-child.c (startup_inferior): Pass 0 as options to
	target_wait (blocking wait).
	* linux-nat.c (linux_nat_create_inferior): Remove async masking.
	(linux_nat_wait_1): Add `target_options' argument.  Use it instead
	of checking on target_can_async_p.
	(linux_nat_wait): Add `target_options' argument.  Adjust.
	* remote.c (remote_wait_ns): Add `options' argument.  Adjust to
	check on TARGET_WNOWAIT instead of checking on remote_is_async_p.
	(remote_wait_as): Add `options' argument.  Adjust to check on
	TARGET_WNOWAIT instead of checking on remote_is_async_p.  If doing
	a blocking wait, keep waiting until an interesting event comes
	out.
	(remote_wait): Add `options' argument.  Don't loop here if the
	target is in async mode, and a blocking wait has been requested.

	* top.c (deprecated_target_wait_hook): Add `options' argument.
	* linux-thread-db.c (thread_db_wait): Add `options' argument, and
	pass it down to the layer beneath.
	* inf-ptrace.c (inf_ptrace_wait): Add `options' argument.
	* record.c (record_beneath_to_wait): Add `options' argument.
	(record_wait): Add `options' argument, and pass it down to the
	layer beneath.
	* bsd-uthread.c (bsd_uthread_wait): Add `options' argument.
	* darwin-nat.c (darwin_wait): Likewise.
	* defs.h (deprecated_target_wait_hook): Likewise.
	* gnu-nat.c (gnu_wait): Add `options' argument.
	* go32-nat.c (go32_wait): Likewise.
	* hpux-thread.c (hpux_thread_wait): Add `options' argument, and
	pass it down to the layer beneath.
	* inf-ttrace.c (inf_ttrace_wait): Add `options' argument.
	* monitor.c (monitor_wait): Likewise.
	* nto-procfs.c (procfs_wait): Likewise.
	* remote-mips.c (mips_wait): Add `options' argument.
	* remote-sim.c (gdbsim_wait): Likewise.
	* rs6000-nat.c (rs6000_wait): Add `options' argument.
	* sol-thread.c (sol_thread_wait): Add `options' argument, and pass
	it down to the layer beneath.
	* spu-linux-nat.c (spu_child_wait): Add `options' argument.
	* windows-nat.c (windows_wait): Likewise.
	* tui/tui-hooks.c (tui_target_wait_hook): Likewise.  Adjust.

gdb/remote.c

@@ -4646,7 +4646,7 @@ process_stop_reply (struct stop_reply *stop_reply,
 /* The non-stop mode version of target_wait.  */
 
 static ptid_t
-remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
+remote_wait_ns (ptid_t ptid, struct target_waitstatus *status, int options)
 {
   struct remote_state *rs = get_remote_state ();
   struct remote_arch_state *rsa = get_remote_arch_state ();
@@ -4688,16 +4688,15 @@ remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
       if (stop_reply != NULL)
 	return process_stop_reply (stop_reply, status);
 
-      /* Still no event.  If we're in asynchronous mode, then just
+      /* Still no event.  If we're just polling for an event, then
 	 return to the event loop.  */
-      if (remote_is_async_p ())
+      if (options & TARGET_WNOHANG)
 	{
 	  status->kind = TARGET_WAITKIND_IGNORE;
 	  return minus_one_ptid;
 	}
 
-      /* Otherwise, asynchronous mode is masked, so do a blocking
-	 wait.  */
+      /* Otherwise do a blocking wait.  */
       ret = getpkt_or_notif_sane (&rs->buf, &rs->buf_size,
 				  1 /* forever */);
     }
@@ -4707,7 +4706,7 @@ remote_wait_ns (ptid_t ptid, struct target_waitstatus *status)
    STATUS just as `wait' would.  */
 
 static ptid_t
-remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
+remote_wait_as (ptid_t ptid, struct target_waitstatus *status, int options)
 {
   struct remote_state *rs = get_remote_state ();
   struct remote_arch_state *rsa = get_remote_arch_state ();
@@ -4717,6 +4716,8 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
   char *buf, *p;
   struct stop_reply *stop_reply;
 
+ again:
+
   status->kind = TARGET_WAITKIND_IGNORE;
   status->value.integer = 0;
 
@@ -4819,8 +4820,14 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
     }
 
   if (status->kind == TARGET_WAITKIND_IGNORE)
-    /* Nothing interesting happened.  */
-    return minus_one_ptid;
+    {
+      /* Nothing interesting happened.  If we're doing a non-blocking
+	 poll, we're done.  Otherwise, go back to waiting.  */
+      if (options & TARGET_WNOHANG)
+	return minus_one_ptid;
+      else
+	goto again;
+    }
   else if (status->kind != TARGET_WAITKIND_EXITED
 	   && status->kind != TARGET_WAITKIND_SIGNALLED)
     {
@@ -4841,24 +4848,14 @@ remote_wait_as (ptid_t ptid, struct target_waitstatus *status)
 
 static ptid_t
 remote_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *status)
+	     ptid_t ptid, struct target_waitstatus *status, int options)
 {
   ptid_t event_ptid;
 
   if (non_stop)
-    event_ptid = remote_wait_ns (ptid, status);
+    event_ptid = remote_wait_ns (ptid, status, options);
   else
-    {
-      /* In synchronous mode, keep waiting until the target stops.  In
-	 asynchronous mode, always return to the event loop.  */
-
-      do
-	{
-	  event_ptid = remote_wait_as (ptid, status);
-	}
-      while (status->kind == TARGET_WAITKIND_IGNORE
-	     && !target_can_async_p ());
-    }
+    event_ptid = remote_wait_as (ptid, status, options);
 
   if (target_can_async_p ())
     {