Fix warnings about ignored return values.

apps/speed.c

@@ -2644,7 +2644,11 @@ static int do_multi(int multi)
 	fds=malloc(multi*sizeof *fds);
 	for(n=0 ; n < multi ; ++n)
 		{
-		pipe(fd);
+		if (pipe(fd) == -1)
+			{
+			fprintf(stderr, "pipe failure\n");
+			exit(1);
+			}
 		fflush(stdout);
 		fflush(stderr);
 		if(fork())
@@ -2656,7 +2660,11 @@ static int do_multi(int multi)
 			{
 			close(fd[0]);
 			close(1);
-			dup(fd[1]);
+			if (dup(fd[1]) == -1)
+				{
+				fprintf(stderr, "dup failed\n");
+				exit(1);
+				}
 			close(fd[1]);
 			mr=1;
 			usertime=0;