RP2040: usb: fix USB_DEVICE_ENUMERATION_FIX linking

Author: facchinm

targets/TARGET_RASPBERRYPI/TARGET_RP2040/USBPhy_RP2040.cpp

@@ -16,6 +16,11 @@
  */
 
 #include "USBPhyHw.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 // USB register definitions from pico-sdk
 #include "hardware/regs/usb.h"
 // USB hardware struct definitions from pico-sdk
@@ -29,6 +34,10 @@
 #include "rp2040_usb_device_enumeration.h"
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 // These accessor functions are used to implement bit clear / bit sets through
 // an atomic alias (this handles the state where both cores can access a register
 // and cause a bit loss through a read-modify-write access)

targets/targets.json

@@ -8020,6 +8020,7 @@
     "NANO_RP2040_CONNECT": {
         "inherits": ["RP2040"],
         "macros_add": [
+            "PICO_RP2040_USB_DEVICE_ENUMERATION_FIX=1",
             "PICO_NO_BINARY_INFO=1",
             "MBED_MPU_CUSTOM",
             "PICO_TIME_DEFAULT_ALARM_POOL_DISABLED",