+Some systems allow a superuser to unlink directories, even though this
+can cause file system corruption. The error given if a process is not
+permitted to unlink directories varies across implementations; it is
+not always the POSIX value of @code{EPERM}. Meanwhile, if a process
+has the ability to unlink directories, POSIX requires that
+@code{unlink("symlink-to-dir/")} remove @file{dir} and leave
+@file{symlink-to-dir} dangling; this behavior is counter-intuitive.
+The gnulib module unlinkdir can help determine whether code must be
+cautious of unlinking directories.
+@item