- Simplify, prefer readability
- Fix nftw() 'nopenfd' argument
- Constify
The most interesting change is the argument to nftw(), 0 -> 20, to
ensure it is allowed to open enough file descriptors to descend.
In POSIX it is undefined if nopenfd is < 1.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>