runtime/qio: use getcwd instead of getwd

getwd is deprecated in favor of getcwd.

Related to #325.
I'm able to create it, but using bash I can't cd into it, while with csh I can:

```
% cd $dir1
% cd $dir2
% pwd
pwd: .: File name too long
% cd ${dir1}${dir2}
/tmp/[...]/b: File name too long.
```

In bash, I get the ENOENT error:

```
% bash -c "cd $dir1; cd $dir2"
cd: error retrieving current directory: getcwd: cannot access parent directories: No such file or directory
```

I think I give up x)