Fixed segfault

elementary/benchmark/main.c

@@ -39,6 +39,7 @@ double compute_next_chunk_elems(struct dispatch_context *dc, struct futhark_cont
         futhark_context_sync(fc);
         if (i + 1 < N_ITERATIONS) {
             futhark_free_i8_1d(fc, fut_next_chunk_elems);
+            futhark_context_sync(fc);
         }
     }
     futhark_values_i8_1d(fc, fut_next_chunk_elems, ci->data);

game_of_life/benchmark/main.c

@@ -43,6 +43,7 @@ double compute_next_chunk_board(struct dispatch_context *dc, struct futhark_cont
         futhark_context_sync(fc);
         if (i + 1 < N_ITERATIONS) {
             futhark_free_i8_2d(fc, fut_next_chunk_board);
+            futhark_context_sync(fc);
         }
     }
     futhark_values_i8_2d(fc, fut_next_chunk_board, ci->data);

lattice_boltzmann/main.c

@@ -51,6 +51,7 @@ double compute_next_lbm(struct dispatch_context *dc, struct futhark_context *fc,
         futhark_context_sync(fc);
         if (i + 1 < N_ITERATIONS) {
             futhark_free_f32_4d(fc, fut_next_chunk_lbm);
+            futhark_context_sync(fc);
         }
     }
     futhark_values_f32_4d(fc, fut_next_chunk_lbm, ci->data);