Get a weird problem out of the way for now

See #31

src/fellow_log_test.c

@@ -717,7 +717,8 @@ forkrun(const struct tc *tc, double killafter, void *t_priv)
 	DBG("killtimer %f", killafter);
 	i = sigtimedwait(&mask, NULL, &timeo);
 	if (i < 0) {
-		assert(errno == EAGAIN);
+		// XXX WHY EINTR? #31
+		assert(errno == EAGAIN || errno == EINTR);
 		i = kill(pid, SIGABRT);
 		assert(i == 0 || i == ESRCH);
 	}