implement Fileinfo for Windows and non-Windows

internal/internal_windows.go

@@ -0,0 +1,12 @@
+//go:build windows
+
+package internal
+
+import (
+	"os"
+)
+
+// Fileinfo returns syscall fields from a FileInfo object.
+func Fileinfo(fi os.FileInfo) (uid, gid int) {
+	return -1, -1
+}