text: 
  #ifndef ERRNO_H
  #define ERRNO_H
  
  #if defined(__linux__) && defined(__x86_64)
  
  int *__errno_location();
  #define errno (*__errno_location())
  
  #elif defined(__CYGWIN__) && defined(__x86_64)
  
  #define errno (*__errno())
  extern int *__errno(void);
  
  #else
  
  static_assert(0, "Unsupported enviroment");
  
  #endif
  
  #endif
  