warning: unused parameter or name

would be nice to fix this warn

```
In file included from D:\git\boost_\libs\process\include\boost/process/v1/io.hpp:14:
D:\git\boost_\libs\process\include\boost/process/v1/pipe.hpp(399,35): warning: unused parameter 'name' [-Wunused-parameter]
399 | void open(const std::string & name)
| ^
D:\git\boost_\libs\process\include\boost/process/v1/pipe.hpp(507,35): warning: unused parameter 'name' [-Wunused-parameter]
507 | void open(const std::string & name)
| ^
D:\git\boost_\libs\process\include\boost/process/v1/pipe.hpp(615,35): warning: unused parameter 'name' [-Wunused-parameter]
615 | void open(const std::string & name)
| ^
```

```
D:\git\boost_\libs\process\include\boost/process/v1/detail/windows/handles.hpp(141,45): warning: unused variable 'flags' [-Wunused-variable]
141 | ::boost::winapi::DWORD_ flags = 0u;
| ^~~~~
D:\git\boost_\libs\process\include\boost/process/v1/detail/windows/handles.hpp(157,30): warning: unused parameter 'exec' [-Wunused-parameter]
157 | void on_error(Executor & exec, const std::error_code & ec) const
| ^
D:\git\boost_\libs\process\include\boost/process/v1/detail/windows/handles.hpp(157,60): warning: unused parameter 'ec' [-Wunused-parameter]
157 | void on_error(Executor & exec, const std::error_code & ec) const
| ^
D:\git\boost_\libs\process\include\boost/process/v1/detail/windows/handles.hpp(164,32): warning: unused parameter 'exec' [-Wunused-parameter]
164 | void on_success(Executor & exec) const
| ^

```