Fix 'unused variable' warning in testCbrt.c

tests/testCbrt.c

@@ -50,8 +50,9 @@ int main(int argc, char *argv[]) {
   message("executing %i runs of each command.", num_vals);
 
   /* Create and fill an array of floats. */
-  float *data;
-  posix_memalign((void **)&data, 64, num_vals * sizeof(float));
+  float *data = NULL;
+  if (posix_memalign((void **)&data, 64, num_vals * sizeof(float)) != 0)
+    error("Failed to allocted memory for the test");
   for (int k = 0; k < num_vals; k++) {
     data[k] = (float)rand() / RAND_MAX;
     data[k] = (1.0f - data[k]) * range_min + data[k] * range_max;