fix map() command on 32-bit platforms; regressed in 5.2.0
LuaJIT FFI was using opendir() (etc.) variants with 32-bit inodes
but the C parts was using them as 64-bit inode variants.
Consequently the struct dirent
layout didn't match and we were getting
filenames shifted by eight bytes.
Now the whole dir-listing lua function is written in C.
Edited by Vladimír Čunát