无法在cygwin上编译故意的文件

Question

编译vim插件color_coded时会出现问题，可归纳如下：

1. 使用g++ -std=c++14，symlink无法找到unistd.h。
2. 使用clang++ -std=c++14，cygwin不支持mutex。

那么，如何在cygwin上编译这段代码？

#include <unistd.h>
#include <mutex>
#include <thread>
#include <iostream>

std::mutex io_mutex;
auto foo(){
   std::lock_guard<std::mutex> guard{io_mutex};
   std::cout << &symlink << "\n";
}

int main(){
   std::thread t1{foo}, t2{foo};
   t1.join();
   t2.join();
}

以下是错误。

1. gcc 5.4.0和g++ -std=c++14：

   t.cpp: In function 'auto foo()':
   t.cpp:9:18: error: 'symlink' was not declared in this scope
       std::cout << &symlink << "\n";
   

2. 使用clang 3.7.1和clang++ -std=c++14：

   In file included from t.cpp:2:
   /usr/lib/gcc/i686-pc-cygwin/5.4.0/include/c++/mutex:699:10: error: thread-local
         storage is not supported for the current target
     extern __thread void* __once_callable;
            ^
   /usr/lib/gcc/i686-pc-cygwin/5.4.0/include/c++/mutex:700:10: error: thread-local
         storage is not supported for the current target
     extern __thread void (*__once_call)();
            ^
   2 errors generated.