ftw.3: Add examples
Given that POSIX.1-2008tc2 says that ftw() is obsolete and applications should use nftw() instead, it seems better to have the example use nftw() instead.
can be used.
Not having a default in this switch feels somewhat uncomfortable, especially because POSIX says FTW_SL is a valid value here.
Paranoia in case the code is edited to remove cases or to add a flag (that does not exist yet) requesting a new typeflag value. Initializing type or adding a default would avoid that.