neutrino: avoid destructors running on exit on sh4

after all cleanup there were still (openthread related?) crashes at
exit in the destructors, so finally simply disable them
The crashes ranged from unaligned access (SIGBUS) to malloc errors
to plain SIGSEGV.

src/neutrino.cpp

@@ -3189,8 +3189,12 @@ void CNeutrinoApp::ExitRun(const bool /*write_si*/, int retcode)
 
 			printf("[neutrino] This is the end. exiting with code %d\n", retcode);
 			Cleanup();
-			//_exit(retcode);
+#ifdef __sh__
+			/* the sh4 gcc seems to dislike someting about openthreads... */
+			_exit(retcode);
+#else
 			exit(retcode);
+#endif
 #if HAVE_COOL_HARDWARE
 		}
 #endif
@@ -3759,8 +3763,11 @@ void sighandler (int signum)
 		delete CVFD::getInstance();
 		delete SHTDCNT::getInstance();
 		stop_video();
-		//_exit(0);
+#ifdef __sh__
+		_exit(0);
+#else
 		exit(0);
+#endif
 	default:
 		break;
 	}