Don't leak setup_struct into Arduino sketch namespace

teensy3/usb_audio.cpp

 	return target * 4;
 }
 
+
+struct setup_struct {
+  union {
+    struct {
+	uint8_t bmRequestType;
+	uint8_t bRequest;
+	union {
+		struct {
+			uint8_t bChannel;  // 0=main, 1=left, 2=right
+			uint8_t bCS;       // Control Selector
+		};
+		uint16_t wValue;
+	};
+	union {
+		struct {
+			uint8_t bIfEp;     // type of entity
+			uint8_t bEntityId; // UnitID, TerminalID, etc.
+		};
+		uint16_t wIndex;
+	};
+	uint16_t wLength;
+    };
+  };
+};
+
 int usb_audio_get_feature(void *stp, uint8_t *data, uint32_t *datalen)
 {
 	struct setup_struct setup = *((struct setup_struct *)stp);

teensy3/usb_audio.h

 #ifdef __cplusplus
 }
 
-// setup struct definition could be moved from usb_dev.c to usb_dev.h so we can reuse 
-// it instead of redefining it here
-struct setup_struct {
-  union {
-    struct {
-	uint8_t bmRequestType;
-	uint8_t bRequest;
-	union {
-		struct {
-			uint8_t bChannel;  // 0=main, 1=left, 2=right
-			uint8_t bCS;       // Control Selector
-		};
-		uint16_t wValue;
-	};
-	union {
-		struct {
-			uint8_t bIfEp;     // type of entity
-			uint8_t bEntityId; // UnitID, TerminalID, etc.
-		};
-		uint16_t wIndex;
-	};
-	uint16_t wLength;
-    };
-  };
-};
-
 // audio features supported
 struct usb_audio_features_struct {
   int change;  // set to 1 when any value is changed