gdb: Use sighandler_t everywhere

This fixes 14 build errors like these in C++ mode:

 src/gdb/extension.c: In function ‘void install_sigint_handler(const signal_handler*)’:
 src/gdb/extension.c:698:41: error: invalid conversion from ‘void (*)()’ to ‘__sighandler_t {aka void (*)(int)}’ [-fpermissive]
    signal (SIGINT, handler_state->handler);
					  ^
 In file included from build-gnulib/import/signal.h:52:0,
		  from ../../src/gdb/extension.c:24:
 /usr/include/signal.h:102:23: error:   initializing argument 2 of ‘void (* signal(int, __sighandler_t))(int)’ [-fpermissive]
  extern __sighandler_t signal (int __sig, __sighandler_t __handler)
			^

Instead of this everywhere:

 -  RETSIGTYPE (*handle_sigint_for_compare) () = handle_sigint;
 +  RETSIGTYPE (*handle_sigint_for_compare) (int) = handle_sigint;

Use sighandler_t (a GNU extension).  That's OK to use unconditionaly
because gnulib's signal.h replacement makes sure that it is available.

gdb/ChangeLog:
2015-08-27  Pedro Alves  <palves@redhat.com>

	* cp-support.c (gdb_demangle): Use sighandler_t.  Remove cast.
	* extension-priv.h: Include signal.h.
	(struct signal_handler) <handler>: Change type to sighandler_t.
	* extension.c (install_gdb_sigint_handler): Use sighandler_t.
	* inflow.c (sigint_ours, sigquit_ours): Change type to
	sighandler_t.
	(child_terminal_inferior): Remove casts.
	(child_terminal_ours_1, new_tty): Use sighandler_t.  Remove casts.
	(osig): Change type to sighandler_t.
	* nto-procfs.c (ofunc): Change type to sighandler_t.
	(procfs_wait): Remove casts.
	* remote-m32r-sdi.c (m32r_wait, m32r_load): Use sighandler_t.
	* remote-sim.c (gdbsim_wait): Use sighandler_t.
	* utils.c (wait_to_die_with_timeout): Use sighandler_t.

1 files changed, 2 insertions, 2 deletions

diff --git a/gdb/cp-support.c b/gdb/cp-support.c
index 3995bcc..d3e26ad 100644
--- a/gdb/cp-support.c
+++ b/gdb/cp-support.c
@@ -1535,7 +1535,7 @@ gdb_demangle (const char *name, int options)
 #if defined (HAVE_SIGACTION) && defined (SA_RESTART)
   struct sigaction sa, old_sa;
 #else
-  void (*ofunc) ();
+  sighandler_t ofunc;
 #endif
   static int core_dump_allowed = -1;
 
@@ -1559,7 +1559,7 @@ gdb_demangle (const char *name, int options)
 #endif
       sigaction (SIGSEGV, &sa, &old_sa);
 #else
-      ofunc = (void (*)()) signal (SIGSEGV, gdb_demangle_signal_handler);
+      ofunc = signal (SIGSEGV, gdb_demangle_signal_handler);
 #endif
 
       crash_signal = SIGSETJMP (gdb_demangle_jmp_buf);