This fixes opening files with non-UTF8 sequences in their path (as long
as the file:// URI is %-encoded correctly).

As already stated (I think), this might be wrong. I have no clue what
codeset this file format is supposed to use.

Dynamically allocate the dir list to prevent potential array overflows (I believe that we were writing to the 5th element of a 4 element array since the luac commits).

It is not fatal.