force add cpp file for test

tests_ispcpp/simple.cpp

@@ -0,0 +1,20 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "simple.h"
+
+int main() {
+    double A[256];
+
+    for (int i=0; i<256; i++) {
+        A[i] = i / 11.;
+    }
+
+    ispc::foo(256, (double*)&A);
+
+    for (int i=0; i<256; i++) {
+        printf("%f\n", A[i]);
+    }
+
+    return 0;
+}