Probably the worst problem is that if we are using `char_u`, we have to cast every string literal and the args for external functions:
```
char_u *example = (char_u *)"Literal";
uv_some_function((char *)example);
```
I started converting the use of `char_u` to `char` because I saw this in other pull requests as well.
`char_u` is not only used everywhere for paths, it is used for nearly all strings, but I don't know if there is a good reason for this.