ffmpeg: log error message when shutting down from too many signals

write() suggested by wm4
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

ffmpeg.c

@@ -321,8 +321,11 @@ sigterm_handler(int sig)
     received_sigterm = sig;
     received_nb_signals++;
     term_exit_sigsafe();
-    if(received_nb_signals > 3)
+    if(received_nb_signals > 3) {
+        write(STDERR_FILENO, "Received > 3 system signals, hard exiting\n",
+                      strlen("Received > 3 system signals, hard exiting\n"));
         exit(123);
+    }
 }
 
 void term_init(void)