DOjS:
For DOjS code, written by me, the MIT license below applies.

MuJS
MuJS is released under ISC license.

GRX:
GRX itself is released under LGPL, the fonts are under "MIT and other licenses".
See copying.grx below or in the grx folder for details.

SoundBlaster MIDI, DMA, FM sound and SoundBlaster detection code:
This code (modified by me) is (c) bei Steven Don (http://www.shdon.com/).
It is licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)
with kind permission of Steven. `FM.DAT` is released under WTFPL
(http://www.wtfpl.net/).

IPX and dosbuffer sub-system:
This code is taken from the game Cylindrix by Hotwarez LLC, Goldtree Enterprises.
It was released under GPLv2.

CWSDPMI.EXE:
CWSDPMI (http://sandmann.dotster.com/cwsdpmi/) DPMI host is licensed under GPL.
The documentation states:
> The files in this binary distribution may be redistributed under the GPL
(with source) or without the source code provided.

The DOjS logo dog was downloaded from https://www.pexels.com/photo/animal-cachorro-doge-pug-1753686/ and kindly provided by Iago Garcia Garcia.

The logo font is "Comic relief" (https://www.fontsquirrel.com/fonts/comic-relief) by Jeff Davis provided under SIL OPEN FONT LICENSE Version 1.1.

All WAV files were downloaded from https://bigsoundbank.com/ and are licensed under WTFPL.
* https://bigsoundbank.com/detail-0283-song-of-rooster.html
* https://bigsoundbank.com/detail-1102-bell-bike-5.html
* https://bigsoundbank.com/detail-1023-explosion-far-away.html

The MIDI files were downloaded from the https://github.com/freedoom/freedoom project and are licensed under FreeDOOM license.

libpng is released under PNG Reference Library License version 2.

zlib is released under zlib license.

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MIT License

Copyright (c) 2019 Andre Seidelt <superilu@yahoo.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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ISC License

Copyright (c) 2013, 2017, Artifex Software

Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.

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This is file "copying.grx".

This document describes the terms for distributing the source code of and any
derived work based on the GRX graphics library. Such source code is marked
with the next text:

 ** Copyright (c) [year] [author], [author information]
 **
 ** This file is part of the GRX graphics library.
 **
 ** The GRX graphics library is free software; you can redistribute it
 ** and/or modify it under some conditions; see the "copying.grx" file
 ** for details.

Source code with the above copyright is distributed under the following terms:

 (1) The test programs for the graphics library (code in the 'test'
     sub-directory) is distributed without restrictions. This code
     is free for use in commercial, shareware or freeware applications.

 (2) The GRX graphics library is distributed under the terms of the
     GNU LGPL (Library General Public License) with the following amendments
     and/or exceptions:

     -  Using the DOS versions (DOS only! this exception DOES NOT apply to
	the Linux version) you are permitted to distribute an application
	linked with GRX in binary only, provided that the documentation
	of the program:

	   a)	informs the user that GRX is used in the program, AND

	   b)	provides the user with the necessary information about
		how to obtain GRX. (i.e. ftp site, etc..)

 (3) Fonts (in the 'fonts' sub-directory). Most of the fonts included with
     the GRX library were derived from fonts in the MIT X11R4 distribution.
     They are distributed according to the terms in the file "COPYING.MIT"
     (X license). Exceptions are:
     - The fonts "ter-114b.res", "ter-114n.fna" and "ter-114v.psf" are
       Copyright (C) 2002 Dimitar Zhekov, but are distributed under the
       X license too.
     - The "pc" BIOS font family, which is distributed without restrictions.

A copy of the GNU GPL (in the file "COPYING") and the GNU LGPL (in
the file "COPYING.LIB") is included with this document. If you did
not receive a copy of "COPYING" or "COPYING.LIB", you may obtain one 
from where this document was obtained, or by writing to:

  Free Software Foundation
  675 Mass Ave
  Cambridge, MA 02139
  USA

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Copyright (C) 2001 Hotwarez LLC, Goldtree Enterprises

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation;
version 2 of the License.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

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Copyright (c) 2013, Jeff Davis (info@loudifier.com),
with Reserved Font Name "Comic Relief".

This Font Software is licensed under the SIL Open Font License, Version 1.1.
This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL

-----------------------------------------------------------
SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007
-----------------------------------------------------------

PREAMBLE
The goals of the Open Font License (OFL) are to stimulate worldwide development of collaborative font projects, to support the font creation efforts of academic and linguistic communities, and to provide a free and open framework in which fonts may be shared and improved in partnership with others.

The OFL allows the licensed fonts to be used, studied, modified and redistributed freely as long as they are not sold by themselves. The fonts, including any derivative works, can be bundled, embedded, redistributed and/or sold with any software provided that any reserved names are not used by derivative works. The fonts and derivatives, however, cannot be released under any other type of license. The requirement for fonts to remain under this license does not apply to any document created using the fonts or their derivatives.

DEFINITIONS
"Font Software" refers to the set of files released by the Copyright Holder(s) under this license and clearly marked as such. This may include source files, build scripts and documentation.

"Reserved Font Name" refers to any names specified as such after the copyright statement(s).

"Original Version" refers to the collection of Font Software components as distributed by the Copyright Holder(s).

"Modified Version" refers to any derivative made by adding to, deleting, or substituting -- in part or in whole -- any of the components of the Original Version, by changing formats or by porting the Font Software to a new environment.

"Author" refers to any designer, engineer, programmer, technical writer or other person who contributed to the Font Software.

PERMISSION & CONDITIONS
Permission is hereby granted, free of charge, to any person obtaining a copy of the Font Software, to use, study, copy, merge, embed, modify, redistribute, and sell modified and unmodified copies of the Font Software, subject to the following conditions:

1) Neither the Font Software nor any of its individual components, in Original or Modified Versions, may be sold by itself.

2) Original or Modified Versions of the Font Software may be bundled, redistributed and/or sold with any software, provided that each copy contains the above copyright notice and this license. These can be included either as stand-alone text files, human-readable headers or in the appropriate machine-readable metadata fields within text or binary files as long as those fields can be easily viewed by the user.

3) No Modified Version of the Font Software may use the Reserved Font Name(s) unless explicit written permission is granted by the corresponding Copyright Holder. This restriction only applies to the primary font name as presented to the users.

4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font Software shall not be used to promote, endorse or advertise any Modified Version, except to acknowledge the contribution(s) of the Copyright Holder(s) and the Author(s) or with their explicit written permission.

5) The Font Software, modified or unmodified, in part or in whole, must be distributed entirely under this license, and must not be distributed under any other license. The requirement for fonts to remain under this license does not apply to any document created using the Font Software.

TERMINATION
This license becomes null and void if any of the above conditions are not met.

DISCLAIMER
THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM OTHER DEALINGS IN THE FONT SOFTWARE.

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DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                   Version 2, December 2004
 
Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>

Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
 
           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
  TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

 0. You just DO WHAT THE FUCK YOU WANT TO.
 
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FreeDOOM license

Copyright © 2001-2018
Contributors to the Freedoom project.  All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

  * Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
  * Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
  * Neither the name of the Freedoom project nor the names of its
    contributors may be used to endorse or promote products derived from
    this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS
IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

For a list of contributors to the Freedoom project, see the file
CREDITS.

 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

COPYRIGHT NOTICE, DISCLAIMER, and LICENSE
=========================================

PNG Reference Library License version 2
---------------------------------------

 * Copyright (c) 1995-2018 The PNG Reference Library Authors.
 * Copyright (c) 2018 Cosmin Truta.
 * Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson.
 * Copyright (c) 1996-1997 Andreas Dilger.
 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

The software is supplied "as is", without warranty of any kind,
express or implied, including, without limitation, the warranties
of merchantability, fitness for a particular purpose, title, and
non-infringement.  In no even shall the Copyright owners, or
anyone distributing the software, be liable for any damages or
other liability, whether in contract, tort or otherwise, arising
from, out of, or in connection with the software, or the use or
other dealings in the software, even if advised of the possibility
of such damage.

Permission is hereby granted to use, copy, modify, and distribute
this software, or portions hereof, for any purpose, without fee,
subject to the following restrictions:

 1. The origin of this software must not be misrepresented; you
    must not claim that you wrote the original software.  If you
    use this software in a product, an acknowledgment in the product
    documentation would be appreciated, but is not required.

 2. Altered source versions must be plainly marked as such, and must
    not be misrepresented as being the original software.

 3. This Copyright notice may not be removed or altered from any
    source or altered source distribution.


PNG Reference Library License version 1 (for libpng 0.5 through 1.6.35)
-----------------------------------------------------------------------

libpng versions 1.0.7, July 1, 2000 through 1.6.35, July 15, 2018 are
Copyright (c) 2000-2002, 2004, 2006-2018 Glenn Randers-Pehrson, are
derived from libpng-1.0.6, and are distributed according to the same
disclaimer and license as libpng-1.0.6 with the following individuals
added to the list of Contributing Authors:

    Simon-Pierre Cadieux
    Eric S. Raymond
    Mans Rullgard
    Cosmin Truta
    Gilles Vollant
    James Yu
    Mandar Sahastrabuddhe
    Google Inc.
    Vadim Barkov

and with the following additions to the disclaimer:

    There is no warranty against interference with your enjoyment of
    the library or against infringement.  There is no warranty that our
    efforts or the library will fulfill any of your particular purposes
    or needs.  This library is provided with all faults, and the entire
    risk of satisfactory quality, performance, accuracy, and effort is
    with the user.

Some files in the "contrib" directory and some configure-generated
files that are distributed with libpng have other copyright owners, and
are released under other open source licenses.

libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
libpng-0.96, and are distributed according to the same disclaimer and
license as libpng-0.96, with the following individuals added to the
list of Contributing Authors:

    Tom Lane
    Glenn Randers-Pehrson
    Willem van Schaik

libpng versions 0.89, June 1996, through 0.96, May 1997, are
Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
and are distributed according to the same disclaimer and license as
libpng-0.88, with the following individuals added to the list of
Contributing Authors:

    John Bowler
    Kevin Bracey
    Sam Bushell
    Magnus Holmgren
    Greg Roelofs
    Tom Tanner

Some files in the "scripts" directory have other copyright owners,
but are released under this license.

libpng versions 0.5, May 1995, through 0.88, January 1996, are
Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.

For the purposes of this copyright and license, "Contributing Authors"
is defined as the following set of individuals:

    Andreas Dilger
    Dave Martindale
    Guy Eric Schalnat
    Paul Schmidt
    Tim Wegner

The PNG Reference Library is supplied "AS IS".  The Contributing
Authors and Group 42, Inc. disclaim all warranties, expressed or
implied, including, without limitation, the warranties of
merchantability and of fitness for any purpose.  The Contributing
Authors and Group 42, Inc. assume no liability for direct, indirect,
incidental, special, exemplary, or consequential damages, which may
result from the use of the PNG Reference Library, even if advised of
the possibility of such damage.

Permission is hereby granted to use, copy, modify, and distribute this
source code, or portions hereof, for any purpose, without fee, subject
to the following restrictions:

 1. The origin of this source code must not be misrepresented.

 2. Altered versions must be plainly marked as such and must not
    be misrepresented as being the original source.

 3. This Copyright notice may not be removed or altered from any
    source or altered source distribution.

The Contributing Authors and Group 42, Inc. specifically permit,
without fee, and encourage the use of this source code as a component
to supporting the PNG file format in commercial products.  If you use
this source code in a product, acknowledgment is not required but would
be appreciated.

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/* zlib.h -- interface of the 'zlib' general purpose compression library
  version 1.2.11, January 15th, 2017

  Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  Jean-loup Gailly        Mark Adler
  jloup@gzip.org          madler@alumni.caltech.edu


  The data format used by the zlib library is described by RFCs (Request for
  Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950
  (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format).
*/
