Eliminate immediate_quit

This finally gets rid of immediate_quit (and surrounding
infrustruture), as nothing sets it anymore.

gdb_call_async_signal_handler was only necessary in order to handle
immediate_quit.  We can just call mark_async_signal_handler directly
on all hosts now.

In turn, we can clean up mingw-hdep.c's gdb_select a bit, as
sigint_event / sigint_handler is no longer needed.

gdb/ChangeLog:
2016-04-12  Pedro Alves  <palves@redhat.com>

	* defs.h: Update comments on SIGINT handling.
	(immediate_quit): Delete declaration.
	* event-loop.c (call_async_signal_handler): Delete.
	* event-loop.h (call_async_signal_handler): Delete declaration.
	(mark_async_signal_handler): Update comments.
	(gdb_call_async_signal_handler): Delete declaration.
	* event-top.c (handle_sigint): Call mark_async_signal_handler
	instead of gdb_call_async_signal_handler.
	* exceptions.c (prepare_to_throw_exception): Remove reference to
	immediate_quit.
	(exception_fprintf): Remove comments about immediate_quit.
	* mingw-hdep.c (sigint_event, sigint_handler): Delete.
	(gdb_select): Don't wait on sigint_event.
	(gdb_call_async_signal_handler): Delete.
	(_initialize_mingw_hdep): Delete.
	* posix-hdep.c (gdb_call_async_signal_handler): Delete.
	* utils.c (immediate_quit): Delete.

1 files changed, 4 insertions, 7 deletions

diff --git a/gdb/defs.h b/gdb/defs.h
index 83e4e11..482ef1c 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -125,11 +125,10 @@ extern char *python_libdir;
 /* * Search path for separate debug files.  */
 extern char *debug_file_directory;
 
-/* GDB has two methods for handling SIGINT.  When immediate_quit is
-   nonzero, a SIGINT results in an immediate longjmp out of the signal
-   handler.  Otherwise, SIGINT simply sets a flag; code that might
-   take a long time, and which ought to be interruptible, checks this
-   flag using the QUIT macro.
+/* GDB's SIGINT handler basically sets a flag; code that might take a
+   long time before it gets back to the event loop, and which ought to
+   be interruptible, checks this flag using the QUIT macro, which, if
+   GDB has the terminal, throws a quit exception.
 
    In addition to setting a flag, the SIGINT handler also marks a
    select/poll-able file descriptor as read-ready.  That is used by
@@ -176,8 +175,6 @@ extern void default_quit_handler (void);
 /* Flag that function quit should call quit_force.  */
 extern volatile int sync_quit_force_run;
 
-extern int immediate_quit;
-
 extern void quit (void);
 
 /* Helper for the QUIT macro.  */