[RFC/WIP PATCH 03/14] Flip to set target-async on by default

[Pedro Alves <pedro@codesourcery.com>]

This flips "set target-async" to default to on.  I see no failures
left with this on x86_64-linux, and there used to be none either
against gdbserver, but I haven't tried recently.  One thing left to
decide is what to do with MI.  If the frontend never flips async
explicitly, should we bother to emulate sync MI output, or can we
expect that all frontends can and should cope with async on by default
by now?
---
 gdb/target.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/gdb/target.c b/gdb/target.c
index 3bc4be2..c2aaa7e 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -4259,11 +4259,11 @@ maintenance_print_target_stack (char *cmd, int from_tty)
 }
 
 /* Controls if async mode is permitted.  */
-int target_async_permitted = 0;
+int target_async_permitted = 1;
 
 /* The set command writes to this variable.  If the inferior is
    executing, linux_nat_async_permitted is *not* updated.  */
-static int target_async_permitted_1 = 0;
+static int target_async_permitted_1 = 1;
 
 static void
 set_maintenance_target_async_permitted (char *args, int from_tty,