gdb/ChangeLog
2016-03-19  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* remote.c (remote_pid_to_exec_file): Print warning for unsupported
	PACKET_qXfer_exec_file.

diff --git a/gdb/remote.c b/gdb/remote.c
index af0a08a..d267736 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -12977,7 +12977,13 @@ remote_pid_to_exec_file (struct target_ops *self, int pid)
   char *annex = NULL;
 
   if (packet_support (PACKET_qXfer_exec_file) != PACKET_ENABLE)
-    return NULL;
+    {
+      warning (_("No executable has been specified (see the \"file\" command) "
+                 "and remote gdbserver does not "
+		 "support packet \"qXfer:exec-file:read\""
+		 " - please use FSF gdbserver version 7.10 or later."));
+      return NULL;
+    }
 
   if (filename != NULL)
     xfree (filename);