12310 Add demangle(1) command

*** 19,29 ****
  # CDDL HEADER END
  #
  
  #
  # Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
! # Copyright (c) 2019, Joyent, Inc.
  # Copyright (c) 2012, 2015 by Delphix. All rights reserved.
  # Copyright (c) 2013 DEY Storage Systems, Inc. All rights reserved.
  # Copyright 2014 Garrett D'Amore <garrett@damore.org>
  # Copyright 2016 Toomas Soome <tsoome@me.com>
  # Copyright 2018 Nexenta Systems, Inc.
--- 19,29 ----
  # CDDL HEADER END
  #
  
  #
  # Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
! # Copyright 2019 Joyent, Inc.
  # Copyright (c) 2012, 2015 by Delphix. All rights reserved.
  # Copyright (c) 2013 DEY Storage Systems, Inc. All rights reserved.
  # Copyright 2014 Garrett D'Amore <garrett@damore.org>
  # Copyright 2016 Toomas Soome <tsoome@me.com>
  # Copyright 2018 Nexenta Systems, Inc.
*** 116,125 ****
--- 116,126 ----
          ctwatch         \
          datadm          \
          date            \
          dc              \
          dd              \
+         demangle        \
          deroff          \
          devfsadm        \
          syseventd       \
          devctl          \
          devinfo         \