Update IDF to a0468b2 (#2108)

* Update IDF to a0468b2

* add missing ld file

* Fix PIO builds and change coex policy

tools/sdk/include/bt/esp_gatt_common_api.h

@@ -0,0 +1,51 @@
+// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef __ESP_GATT_COMMON_API_H__
+#define __ESP_GATT_COMMON_API_H__
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "esp_err.h"
+#include "esp_bt_defs.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Maximum Transmission Unit used in GATT
+#define ESP_GATT_DEF_BLE_MTU_SIZE   23   /* relate to GATT_DEF_BLE_MTU_SIZE in stack/gatt_api.h */
+
+// Maximum Transmission Unit allowed in GATT
+#define ESP_GATT_MAX_MTU_SIZE       517  /* relate to GATT_MAX_MTU_SIZE in stack/gatt_api.h */
+
+/**
+ * @brief           This function is called to set local MTU,
+ *                  the function is called before BLE connection.
+ *
+ * @param[in]       mtu: the size of MTU.
+ *
+ * @return
+ *                  - ESP_OK: success
+ *                  - other: failed
+ *
+ */
+extern esp_err_t esp_ble_gatt_set_local_mtu (uint16_t mtu);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __ESP_GATT_COMMON_API_H__ */