> in file included from /usr/include/c++/4.9/cwchar:44:0,
>                  from /usr/include/c++/4.9/bits/postypes.h:40,
>                  from /usr/include/c++/4.9/iosfwd:40,
>                  from /usr/include/c++/4.9/ios:38,
>                  from /usr/include/c++/4.9/ostream:38,
>                  from /include/gtest/gtest.h:55,
>                  from path to unit test header file/_unit_test.h:2,
>                  from path to unit test source file/_unit_test.cpp:1: /usr/include/wchar.h:580:8: error: '__FILE' does not name a type
> extern __FILE *open_wmemstream (wchar_t **__bufloc, size_t *__sizeloc)
> __THROW; /usr/include/wchar.h:587:19: error: '__FILE' was not declared in this scope  extern int fwide (__FILE *__fp, int __mode) __THROW;
>                    ^ /usr/include/wchar.h:587:27: error: '__fp' was not declared in this scope  extern int fwide (__FILE *__fp, int
> __mode) __THROW;
>                            ^ /usr/include/wchar.h:587:33: error: expected primary-expression before 'int'  extern int fwide (__FILE
> *__fp, int __mode) __THROW;
>                                  ^ /usr/include/wchar.h:587:43: error: expression list treated as compound expression in initializer
> [-fpermissive]  extern int fwide (__FILE *__fp, int __mode) __THROW;