Add automatic stack dumping on SIGSEGV and SIGQUIT

Original commit message from CVS:
Add automatic stack dumping on SIGSEGV and SIGQUIT

tools/gst-launch.c

 #include <string.h>
 #include <stdlib.h>
+#include <signal.h>
+#include <sys/wait.h>
 #include <gst/gst.h>
 
 static guint64 iterations = 0;
@@ -104,6 +106,72 @@ xmllaunch_parse_cmdline (const gchar **argv)
     return l->data;
 }
 
+extern volatile gboolean glib_on_error_halt;
+void fault_restore(void);
+
+void fault_handler(int signum, siginfo_t *si, void *misc)
+{
+	int spinning = TRUE;
+
+	fault_restore();
+
+	if(si->si_signo == SIGSEGV){
+		g_print ("Caught SIGSEGV accessing address %p\n", si->si_addr);
+	}else if(si->si_signo == SIGQUIT){
+		g_print ("Caught SIGQUIT\n");
+	}else{
+		g_print ("signo:  %d\n",si->si_signo);
+		g_print ("errno:  %d\n",si->si_errno);
+		g_print ("code:   %d\n",si->si_code);
+	}
+
+	glib_on_error_halt = FALSE;
+	g_on_error_stack_trace("gst-launch");
+
+	wait(NULL);
+
+#if 1
+	/* FIXME how do we know if we were run by libtool? */
+	g_print("Spinning.  Please run 'gdb gst-launch %d' to continue debugging, "
+		"Ctrl-C to quit, or Ctrl-\\ to dump core.\n",
+		getpid());
+	while(spinning)usleep(1000000);
+#else
+	/* This spawns a gdb and attaches it to gst-launch. */
+	{
+		char str[40];
+		sprintf(str,"gdb -quiet gst-launch %d",getpid());
+		system(str);
+	}
+
+	_exit(0);
+#endif
+
+}
+
+void fault_restore(void)
+{
+	struct sigaction action;
+
+	memset(&action,0,sizeof(action));
+	action.sa_handler = SIG_DFL;
+
+	sigaction(SIGSEGV, &action, NULL);
+	sigaction(SIGQUIT, &action, NULL);
+}
+
+void fault_setup(void)
+{
+	struct sigaction action;
+
+	memset(&action,0,sizeof(action));
+	action.sa_sigaction = fault_handler;
+	action.sa_flags = SA_SIGINFO;
+
+	sigaction(SIGSEGV, &action, NULL);
+	sigaction(SIGQUIT, &action, NULL);
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -127,6 +195,8 @@ main(int argc, char *argv[])
 
   free (malloc (8)); /* -lefence */
 
+	fault_setup();
+
   gst_init_with_popt_table (&argc, &argv, options);
   
   /* make a null-terminated version of argv */
@@ -190,3 +260,4 @@ main(int argc, char *argv[])
 
   return 0;
 }
+