use OpenMP (and GCC 4.9 explicitly)

Makefile

-CC = gcc
-CFLAGS = -O2
+CC = gcc-4.9
+CFLAGS = -O2 -fopenmp
 
-FF = gfortran
-FFLAGS = -O2
+FC = gfortran-4.9
+FFLAGS = -O2 -fopenmp
 
 all: stream_f.exe stream_c.exe
 
 stream_f.exe: stream.f mysecond.o
 	$(CC) $(CFLAGS) -c mysecond.c
-	$(FF) $(FFLAGS) -c stream.f
-	$(FF) $(FFLAGS) stream.o mysecond.o -o stream_f.exe
+	$(FC) $(FFLAGS) -c stream.f
+	$(FC) $(FFLAGS) stream.o mysecond.o -o stream_f.exe
 
 stream_c.exe: stream.c
 	$(CC) $(CFLAGS) stream.c -o stream_c.exe

stream.f

@@ -94,7 +94,7 @@
 *     IMPLICIT NONE
 C     .. Parameters ..
       INTEGER n,offset,ndim,ntimes
-      PARAMETER (n=2000000,offset=0,ndim=n+offset,ntimes=10)
+      PARAMETER (n=20000000,offset=0,ndim=n+offset,ntimes=10)
 C     ..
 C     .. Local Scalars ..
       DOUBLE PRECISION scalar,t