Removed 'USB_MANUFACTURER' constant redefinition for known VIDs.

See #1877

Author: cmaglie

avr/cores/arduino/USBCore.cpp

@@ -57,12 +57,18 @@ const u16 STRING_LANGUAGE[2] = {
 const u8 STRING_PRODUCT[] PROGMEM = USB_PRODUCT;
 
 #if USB_VID == 0x2341
-#define USB_MANUFACTURER "Arduino LLC"
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "Arduino LLC"
 #elif USB_VID == 0x1b4f
-#define USB_MANUFACTURER "SparkFun"
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "SparkFun"
 #elif !defined(USB_MANUFACTURER)
 // Fall through to unknown if no manufacturer name was provided in a macro
-#define USB_MANUFACTURER "Unknown"
+#  define USB_MANUFACTURER "Unknown"
 #endif
 
 const u8 STRING_MANUFACTURER[] PROGMEM = USB_MANUFACTURER;