Allow Arduino to be run without BT support in IDF

Fixes: https://github.com/espressif/arduino-esp32/issues/343

Kconfig

@@ -3,7 +3,6 @@ menu "Arduino Configuration"
 config ENABLE_ARDUINO_DEPENDS
     bool
     select LWIP_SO_RCVBUF
-    select BT_ENABLED
     select ETHERNET
     select WIFI_ENABLED
     select ESP32_PHY_CALIBRATION_AND_DATA_STORAGE

cores/esp32/esp32-hal-bt.c

@@ -11,6 +11,7 @@
 // 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.
+#if CONFIG_BT_ENABLED
 
 #include "esp32-hal-bt.h"
 
@@ -62,5 +63,5 @@ bool btStop(){
     return false;
 }
 
-
+#endif
 

cores/esp32/esp32-hal-bt.h

@@ -17,6 +17,8 @@
 
 #include "esp32-hal.h"
 
+#if CONFIG_BT_ENABLED
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -29,4 +31,6 @@ bool btStop();
 }
 #endif
 
+#endif
+
 #endif /* _ESP32_ESP32_HAL_BT_H_ */