Fix QNX build.

Note: this is not an officially supported target.
Contributed by Wen Yang.

src/lj_profile.c

@@ -185,7 +185,11 @@ static void profile_timer_start(ProfileState *ps)
   tm.it_value.tv_sec = tm.it_interval.tv_sec = interval / 1000;
   tm.it_value.tv_usec = tm.it_interval.tv_usec = (interval % 1000) * 1000;
   setitimer(ITIMER_PROF, &tm, NULL);
+#if LJ_TARGET_QNX
+  sa.sa_flags = 0;
+#else
   sa.sa_flags = SA_RESTART;
+#endif
   sa.sa_handler = profile_signal;
   sigemptyset(&sa.sa_mask);
   sigaction(SIGPROF, &sa, &ps->oldsa);