remove -Wnested-externs since many driver does this including CMSIS_5

examples/make.mk

@@ -72,7 +72,6 @@ CFLAGS += \
 	-Wsign-compare \
 	-Wmissing-format-attribute \
 	-Wno-deprecated-declarations \
-	-Wnested-externs \
 	-Wunreachable-code \
 	-Wno-error=lto-type-mismatch \
 	-ffunction-sections \

hw/bsp/lpcxpresso11u37/board.mk

@@ -12,7 +12,7 @@ CFLAGS += \
   -DCFG_TUSB_MEM_ALIGN='__attribute__((aligned(64)))' 
 
 # mcu driver cause following warnings
-CFLAGS += -Wno-error=nested-externs -Wno-error=strict-prototypes -Wno-error=unused-parameter
+CFLAGS += -Wno-error=strict-prototypes -Wno-error=unused-parameter
 
 MCU_DIR = hw/mcu/nxp/lpcopen/lpc11uxx/lpc_chip_11uxx
 

hw/bsp/lpcxpresso1347/board.mk

@@ -12,7 +12,7 @@ CFLAGS += \
   -DCFG_TUSB_MEM_ALIGN='__attribute__((aligned(64)))' 
 
 # startup.c and lpc_types.h cause following errors
-CFLAGS += -Wno-error=nested-externs -Wno-error=strict-prototypes
+CFLAGS += -Wno-error=strict-prototypes
 
 MCU_DIR = hw/mcu/nxp/lpcopen/lpc13xx/lpc_chip_13xx
 

hw/bsp/lpcxpresso51u68/board.mk

@@ -9,7 +9,7 @@ CFLAGS += \
   -DCFG_TUSB_MEM_ALIGN='__attribute__((aligned(64)))' 
 
 # mcu driver cause following warnings
-CFLAGS += -Wno-error=nested-externs -Wno-error=unused-parameter
+CFLAGS += -Wno-error=unused-parameter
 
 MCU_DIR = hw/mcu/nxp/sdk/devices/LPC51U68
 

hw/bsp/lpcxpresso55s69/board.mk

@@ -11,7 +11,7 @@ CFLAGS += \
   -DCFG_TUSB_MEM_ALIGN='__attribute__((aligned(64)))'
 
 # mcu driver cause following warnings
-CFLAGS += -Wno-error=unused-parameter -Wno-error=float-equal -Wno-error=nested-externs
+CFLAGS += -Wno-error=unused-parameter -Wno-error=float-equal
 
 MCU_DIR = hw/mcu/nxp/sdk/devices/LPC55S69
 

hw/bsp/mbed1768/board.mk

@@ -10,7 +10,7 @@ CFLAGS += \
   -DRTC_EV_SUPPORT=0
 
 # startup.c and lpc_types.h cause following errors
-CFLAGS += -Wno-error=nested-externs -Wno-error=strict-prototypes
+CFLAGS += -Wno-error=strict-prototypes
 
 MCU_DIR = hw/mcu/nxp/lpcopen/lpc175x_6x/lpc_chip_175x_6x