fmt.Fprintf(&buf, "\n")

	override := make(map[string]string)

	// Allow source file to specify override mappings.
	// For example, the socket data structures refer
	// to in_addr and in_addr6 structs but we want to be
	// able to treat them as byte arrays, so the godefs
	// inputs in package syscall say
	//
	//	// +godefs map struct_in_addr [4]byte

[TestFS] now returns a structured error that can be unwrapped
(via method `Unwrap() []error`). This allows inspecting errors