Currently sysdeps/posix/remove.c reads this:

#v+
int
remove (file)
     const char *file;
{
  /* First try to unlink since this is more frequently the necessary action. */
  if (__unlink (file) != 0
      /* If it is indeed a directory...  */
      && (errno != EISDIR
	  /* ...try to remove it.  */
	  || __rmdir (file) != 0))
    /* Cannot remove the object for whatever reason.  */
    return -1;

  return 0;
}
#v-

However, POSIX says unlink(2) returns `EPERM' when PATH is a directory. `EISDIR'
is Linux-specific and the "Rationale" section at
http://www.opengroup.org/onlinepubs/9699919799/functions/unlink.html says that
"[a]pplications written for portability to both POSIX.1-2008 and the LSB should
be prepared to handle either error code."

Currently remove(3) fails on GNU/Hurd [0] and GNU/kFreeBSD [1] because of this.
 Thus it should be changed to handle both `EPERM' and `EISDIR'.

[0] https://savannah.gnu.org/bugs/?28859
[1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=557248