arduino多线程

我现在调用Arduino的ProtoThread库，可是编译的时候报错了:
Arduino:1.6.6 (Windows 10), 开发板："Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"

C:\Users\Administrator\Documents\Arduino\libraries\ProtoThreads\examples\ExampleSmall\ExampleSmall.pde: In function 'int protothread1(pt*)':

ExampleSmall:24: error: 'int protothread1(pt*)' was declared 'extern' and later 'static' [-fpermissive]

static int protothread1(struct pt *pt)

                                      ^

ExampleSmall:24: error: previous declaration of 'int protothread1(pt*)' [-fpermissive]

static int protothread1(struct pt *pt)

     ^

C:\Users\Administrator\Documents\Arduino\libraries\ProtoThreads\examples\ExampleSmall\ExampleSmall.pde: In function 'int protothread2(pt*)':

ExampleSmall:53: error: 'int protothread2(pt*)' was declared 'extern' and later 'static' [-fpermissive]

static int protothread2(struct pt *pt)

                                      ^

ExampleSmall:25: error: previous declaration of 'int protothread2(pt*)' [-fpermissive]

{

     ^

exit status 1
'int protothread1(pt*)' was declared 'extern' and later 'static' [-fpermissive]

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  "在编译时，输出详细信息"
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是怎么一回事？

看不懂哦，路过哈哈哈