Fixing an error.

config.h

@@ -82,7 +82,7 @@
 //* HARDWARE SETTINGS
 //*************************************************************************************************
 
-#define USB_AUDIO 1
+//#define USB_AUDIO 1
 
 // Teensy Audio Shield:
 /* Values for SGTL5000_LINEOUT_LEVEL

midi_devices.hpp

@@ -26,6 +26,8 @@
 
 #include "config.h"
 
+extern config_t configuration;
+
 /* #if defined(MIDI_DEVICE_USB)
   #include <midi_UsbTransport.h>
   #endif */
@@ -330,9 +332,9 @@ void handleAfterTouchPoly_MIDI_DEVICE_DIN(byte inChannel, byte inNumber, byte in
   Serial.print(F("[MIDI_DIN] AT-Poly"));
 #endif
 #ifdef MIDI_MERGE_THRU
-#ifdef MIDI_DEVICE_USB_HOST
   if (configuration.midi_soft_thru == true)
   {
+#ifdef MIDI_DEVICE_USB_HOST
     midi_usb.sendAfterTouch(inNumber, inVelocity, inChannel);
 #ifdef SHOW_DEBUG
     Serial.print(F(" THRU->MIDI_USB_HOST"));