From 10a8ef7614b1f154576c6b3cdd14f15d1b18a443 Mon Sep 17 00:00:00 2001
From: hathach <thach@tinyusb.org>
Date: Wed, 29 Jul 2020 17:04:47 +0700
Subject: [PATCH] fix nested extern declaration of 'SystemCoreClock'
 [-Werror=nested-externs]

---
 src/portable/st/synopsys/dcd_synopsys.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/portable/st/synopsys/dcd_synopsys.c b/src/portable/st/synopsys/dcd_synopsys.c
index 7eb63e52f..03c33c598 100644
--- a/src/portable/st/synopsys/dcd_synopsys.c
+++ b/src/portable/st/synopsys/dcd_synopsys.c
@@ -231,6 +231,7 @@ static void bus_reset(uint8_t rhport)
 }
 
 // Set turn-around timeout according to link speed
+extern uint32_t SystemCoreClock;
 static void set_turnaround(USB_OTG_GlobalTypeDef * usb_otg, tusb_speed_t speed)
 {
   usb_otg->GUSBCFG &= ~USB_OTG_GUSBCFG_TRDT;
@@ -243,7 +244,6 @@ static void set_turnaround(USB_OTG_GlobalTypeDef * usb_otg, tusb_speed_t speed)
   else
   {
     // Turnaround timeout depends on the MCU clock
-    extern uint32_t SystemCoreClock;
     uint32_t turnaround;
 
     if ( SystemCoreClock >= 32000000U )