Suppress SIGTTOU when handling errors

Calls to error () can cause SIGTTOU to send gdb to the background.

For example, on an Arm build:
  (gdb) b main
  Breakpoint 1 at 0x10774: file /build/gdb/testsuite/../../../src/binutils-gdb/gdb/testsuite/gdb.base/watchpoint.c, line 174.
  (gdb) r
  Starting program: /build/gdb/testsuite/outputs/gdb.base/watchpoint/watchpoint

  [1]+  Stopped                 ../gdb ./outputs/gdb.base/watchpoint/watchpoint
  localhost$ fg
  ../gdb ./outputs/gdb.base/watchpoint/watchpoint
  Cannot parse expression `.L1199 4@r4'.
  warning: Probes-based dynamic linker interface failed.
  Reverting to original interface.

The SIGTTOU is raised whilst inside a syscall during the call to tcdrain.
Fix is to use scoped_ignore_sigttou to ensure SIGTTOU is blocked.

In addition fix include comments - job_control is not included via terminal.h

gdb/ChangeLog:

	* event-top.c: Remove include comment.
	* inflow.c (class scoped_ignore_sigttou): Move from here...
	* inflow.h (class scoped_ignore_sigttou): ...to here.
	* ser-unix.c (hardwire_drain_output): Block SIGTTOU during drain.
	* top.c:  Remove include comment.

1 files changed, 1 insertions, 1 deletions

diff --git a/gdb/top.c b/gdb/top.c
index bacd684..1e17ebe 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -34,7 +34,7 @@
 #include "expression.h"
 #include "value.h"
 #include "language.h"
-#include "terminal.h"		/* For job_control.  */
+#include "terminal.h"
 #include "common/job-control.h"
 #include "annotate.h"
 #include "completer.h"