MSYS error again

```
└> > curl -sfL git.io/antibody | sh -s - -b /usr/bin
getantibody/antibody crit uname_os_check 'MSYS_NT-10.0-16299' got converted to 'msys_nt-10.0-16299' which is not a GOOS value. Please file bug at https://github.com/client9/shlib
```

See https://github.com/client9/shlib/issues/3 and https://github.com/client9/shlib/issues/13