squeeze the usb identification code

Author: dhalbert

supervisor/shared/usb/usb.c

@@ -122,7 +122,9 @@ void usb_set_defaults(void) {
     #endif
 };
 
+#if CIRCUITPY_USB_IDENTIFICATION
 supervisor_allocation *usb_identification_allocation;
+#endif
 
 // Some dynamic USB data must be saved after boot.py. How much is needed?
 size_t usb_boot_py_data_size(void) {
@@ -137,16 +139,21 @@ size_t usb_boot_py_data_size(void) {
 
 // Fill in the data to save.
 void usb_get_boot_py_data(uint8_t *temp_storage, size_t temp_storage_size) {
+    #if CIRCUITPY_USB_IDENTIFICATION
     if (usb_identification_allocation) {
         memcpy(temp_storage, usb_identification_allocation->ptr, sizeof(usb_identification_t));
         free_memory(usb_identification_allocation);
+    #else
+    if (false) {
+        // Nothing
+        #endif
     } else {
-        usb_identification_t defaults = {
-            .vid = USB_VID,
-            .pid = USB_PID,
-            .manufacturer_name = USB_MANUFACTURER,
-            .product_name = USB_PRODUCT,
-        };
+        usb_identification_t defaults;
+        // This compiles to less code than using a struct initializer.
+        defaults.vid = USB_VID;
+        defaults.pid = USB_PID;
+        strcpy(defaults.manufacturer_name, USB_MANUFACTURER);
+        strcpy(defaults.product_name, USB_PRODUCT);
         memcpy(temp_storage, &defaults, sizeof(defaults));
     }