Fix variable length arrays warning in waves2amr

amr-wind/ocean_waves/relaxation_zones/W2AWaves.H

@@ -64,7 +64,7 @@ struct W2AWavesData : public RelaxZonesBaseData
     // FFTW pointers to store modes ready for ifft
     double *r_eta_mptr = nullptr, *r_u_mptr = nullptr, *r_v_mptr = nullptr,
            *r_w_mptr = nullptr, *au_mptr = nullptr, *av_mptr = nullptr,
-           *aw_mptr = nullptr;
+           *aw_mptr = nullptr, *plan_out = nullptr;
     // ReadModes objects
     ReadModes<std::complex<double>> c_rmodes;
     ReadModes<double> r_rmodes;
@@ -120,6 +120,9 @@ struct W2AWavesData : public RelaxZonesBaseData
         if (aw_mptr) {
             delete[] aw_mptr;
         }
+        if (plan_out) {
+            delete[] plan_out;
+        }
         for (int n = 0; n < (int)plan_vector.size(); ++n) {
             fftw_destroy_plan(plan_vector[n]);
         }

amr-wind/ocean_waves/relaxation_zones/waves2amr_ops.H

@@ -406,6 +406,7 @@ struct ReadInputsOp<W2AWaves>
             wdata.av_mptr = modes_hosgrid::allocate_real(wdata.n0, 1);
             wdata.aw_mptr = modes_hosgrid::allocate_real(wdata.n0, 1);
         }
+        wdata.plan_out = modes_hosgrid::allocate_real(wdata.n0, wdata.n1);
 
         // Set up planner flag based on input
         auto plan_f = modes_hosgrid::planner_flags::estimate;
@@ -424,11 +425,12 @@ struct ReadInputsOp<W2AWaves>
         if (wdata.is_ocean) {
             wdata.plan_vector.emplace_back(
                 modes_hosgrid::plan_ifftw(
-                    wdata.n0, wdata.n1, wdata.c_eta_mptr, plan_f));
+                    wdata.n0, wdata.n1, wdata.c_eta_mptr, wdata.plan_out,
+                    plan_f));
         } else {
             modes_hosgrid::plan_ifftw_nwt(
                 wdata.n0, wdata.n1, wdata.plan_vector, wdata.r_eta_mptr,
-                plan_f);
+                wdata.plan_out, plan_f);
         }
 
         // Create height vector for velocity mode conversion before