Make sure that fork_test.c is not built under windows

utest/test_fork.c

@@ -30,6 +30,7 @@ USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 **********************************************************************************/
 
+#ifndef OS_WINDOWS
 #include "common_utest.h"
 #include <sys/wait.h>
 #include <cblas.h>
@@ -56,7 +57,6 @@ void check_dgemm(double *a, double *b, double *result, double *expected, int n)
     }
 }
 
-
 void test_fork_safety(void)
 {
     int n = 1000;
@@ -120,3 +120,4 @@ void test_fork_safety(void)
         CU_ASSERT(WEXITSTATUS (child_status) == 0);
     }
 }
+#endif