fix zdotu argument passing in utest_ext on windows (#4691)

* fix passing of results on windows

utest/test_extensions/test_cgemv_t.c

@@ -74,7 +74,11 @@ static void matrix_vector_product(blasint n, blasint m, blasint lda, blasint inc
 
     for (i = 0; i < n * inc_x; i+= inc_x)
     {
+#ifdef RETURN_BY_STACK
+        BLASFUNC(cdotu)(&result, &lda, a_ptr, &one, x_ptr, &inc_x);
+#else
         result = BLASFUNC(cdotu)(&lda, a_ptr, &one, x_ptr, &inc_x);
+#endif
         x_res[0] = CREAL(result);
         x_res[1] = CIMAG(result);
         a_ptr += lda * 2;

utest/test_extensions/test_zgemv_t.c

@@ -74,8 +74,12 @@ static void matrix_vector_product(blasint n, blasint m, blasint lda, blasint inc
 
     for (i = 0; i < n * inc_x; i += inc_x)
     {
-        result = BLASFUNC(zdotu)(&lda, a_ptr, &one, x_ptr, &inc_x);
-        x_res[0] = CREAL(result);
+#ifdef RETURN_BY_STACK
+       BLASFUNC(zdotu)(&result, &lda, a_ptr, &one, x_ptr, &inc_x);
+#else
+       result = BLASFUNC(zdotu)(&lda, a_ptr, &one, x_ptr, &inc_x);
+#endif
+       x_res[0] = CREAL(result);
         x_res[1] = CIMAG(result);
         a_ptr += lda * 2;
         x_res += 2 * inc_x;