Allow the remote protocol thread id extension on plain target remote.

From: Pedro Alves <palves@redhat.com>


---
 gdb/gdbserver/server.c |    4 ++--
 gdb/remote.c           |   15 +++++++++------
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index a3bc6c9..5ae6795 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -2140,7 +2140,7 @@ handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
 
   if (strncmp (own_buf, "vAttach;", 8) == 0)
     {
-      if (!multi_process && target_running ())
+      if ((!extended_protocol || !multi_process) && target_running ())
 	{
 	  fprintf (stderr, "Already debugging a process\n");
 	  write_enn (own_buf);
@@ -2152,7 +2152,7 @@ handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
 
   if (strncmp (own_buf, "vRun;", 5) == 0)
     {
-      if (!multi_process && target_running ())
+      if ((!extended_protocol || !multi_process) && target_running ())
 	{
 	  fprintf (stderr, "Already debugging a process\n");
 	  write_enn (own_buf);
diff --git a/gdb/remote.c b/gdb/remote.c
index c5c9481..e78853c 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -359,7 +359,7 @@ free_private_thread_info (struct private_thread_info *info)
 static int
 remote_multi_process_p (struct remote_state *rs)
 {
-  return rs->extended && rs->multi_process_aware;
+  return rs->multi_process_aware;
 }
 
 /* This data could be associated with a target, but we do not always
@@ -1713,7 +1713,7 @@ set_general_process (void)
   struct remote_state *rs = get_remote_state ();
 
   /* If the remote can't handle multiple processes, don't bother.  */
-  if (!remote_multi_process_p (rs))
+  if (!rs->extended || !remote_multi_process_p (rs))
     return;
 
   /* We only need to change the remote current thread if it's pointing
@@ -3885,8 +3885,7 @@ remote_query_supported (void)
       char *q = NULL;
       struct cleanup *old_chain = make_cleanup (free_current_contents, &q);
 
-      if (rs->extended)
-	q = remote_query_supported_append (q, "multiprocess+");
+      q = remote_query_supported_append (q, "multiprocess+");
 
       if (remote_support_xml)
 	q = remote_query_supported_append (q, remote_support_xml);
@@ -7440,7 +7439,7 @@ extended_remote_kill (struct target_ops *ops)
   struct remote_state *rs = get_remote_state ();
 
   res = remote_vkill (pid, rs);
-  if (res == -1 && !remote_multi_process_p (rs))
+  if (res == -1 && !(rs->extended && remote_multi_process_p (rs)))
     {
       /* Don't try 'k' on a multi-process aware stub -- it has no way
 	 to specify the pid.  */
@@ -9773,7 +9772,11 @@ remote_supports_multi_process (void)
 {
   struct remote_state *rs = get_remote_state ();
 
-  return remote_multi_process_p (rs);
+  /* Only extended-remote handles being attached to multiple
+     processes, even though plain remote can use the multi-process
+     thread id extensions, so that GDB knows the target process's
+     PID.  */
+  return rs->extended && remote_multi_process_p (rs);
 }
 
 int