Don't assume fileno is a function.
Don't assume fileno is a function.

This otherwise leads to compilation errors when we do `::fileno`
as OpenBSD implemented fileno as a macro (which seems to be allowed).

root-mirror/cling,root-mirror/cling,root-mirror/cling,root-mirror/cling,karies/cling,root-mirror/cling,root-mirror/cling,karies/cling,karies/cling,karies/cling,karies/cling,karies/cling