src/png/README

README for libpng version 1.2.34 - December 18, 2008 (shared library 12.0)
See the note about version numbers near the top of png.h

See INSTALL for instructions on how to install libpng.

Libpng comes in several distribution formats.  Get libpng-*.tar.gz,
libpng-*.tar.lzma, or libpng-*.tar.bz2 if you want UNIX-style line
endings in the text files, or lpng*.7z or lpng*.zip if you want DOS-style
line endings.  You can get UNIX-style line endings from the *.zip file
by using "unzip -a" but there seems to be no simple way to recover
UNIX-style line endings from the *.7z file.  The *.tar.lzma file is
recommended for *NIX users instead.

Version 0.89 was the first official release of libpng.  Don't let the
fact that it's the first release fool you.  The libpng library has been in
extensive use and testing since mid-1995.  By late 1997 it had
finally gotten to the stage where there hadn't been significant
changes to the API in some time, and people have a bad feeling about
libraries with versions < 1.0.  Version 1.0.0 was released in
March 1998.

****
Note that some of the changes to the png_info structure render this
version of the library binary incompatible with libpng-0.89 or
earlier versions if you are using a shared library.  The type of the
"filler" parameter for png_set_filler() has changed from png_byte to
png_uint_32, which will affect shared-library applications that use
this function.

To avoid problems with changes to the internals of png_info_struct,
new APIs have been made available in 0.95 to avoid direct application
access to info_ptr.  These functions are the png_set_<chunk> and
png_get_<chunk> functions.  These functions should be used when
accessing/storing the info_struct data, rather than manipulating it
directly, to avoid such problems in the future.

It is important to note that the APIs do not make current programs
that access the info struct directly incompatible with the new
library.  However, it is strongly suggested that new programs use
the new APIs (as shown in example.c and pngtest.c), and older programs
be converted to the new format, to facilitate upgrades in the future.
****

Additions since 0.90 include the ability to compile libpng as a
Windows DLL, and new APIs for accessing data in the info struct.
Experimental functions include the ability to set weighting and cost
factors for row filter selection, direct reads of integers from buffers
on big-endian processors that support misaligned data access, faster
methods of doing alpha composition, and more accurate 16->8 bit color
conversion.

The additions since 0.89 include the ability to read from a PNG stream
which has had some (or all) of the signature bytes read by the calling
application.  This also allows the reading of embedded PNG streams that
do not have the PNG file signature.  As well, it is now possible to set
the library action on the detection of chunk CRC errors.  It is possible
to set different actions based on whether the CRC error occurred in a
critical or an ancillary chunk.

The changes made to the library, and bugs fixed are based on discussions
on the png-mng-implement mailing list
and not on material submitted privately to Guy, Andreas, or Glenn.  They will
forward any good suggestions to the list.

For a detailed description on using libpng, read libpng.txt.  For
examples of libpng in a program, see example.c and pngtest.c.  For usage
information and restrictions (what little they are) on libpng, see
png.h.  For a description on using zlib (the compression library used by
libpng) and zlib's restrictions, see zlib.h

I have included a general makefile, as well as several machine and
compiler specific ones, but you may have to modify one for your own needs.

You should use zlib 1.0.4 or later to run this, but it MAY work with
versions as old as zlib 0.95.  Even so, there are bugs in older zlib
versions which can cause the output of invalid compression streams for
some images.  You will definitely need zlib 1.0.4 or later if you are
taking advantage of the MS-DOS "far" structure allocation for the small
and medium memory models.  You should also note that zlib is a
compression library that is useful for more things than just PNG files.
You can use zlib as a drop-in replacement for fread() and fwrite() if
you are so inclined.

zlib should be available at the same place that libpng is, or at
ftp://ftp.simplesystems.org/pub/png/src/

You may also want a copy of the PNG specification.  It is available
as an RFC, a W3C Recommendation, and an ISO/IEC Standard.  You can find
these at http://www.libpng.org/pub/png/pngdocs.html

This code is currently being archived at libpng.sf.net in the
[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
at GO GRAPHSUP.  If you can't find it in any of those places,
e-mail me, and I'll help you find it.

If you have any code changes, requests, problems, etc., please e-mail
them to me.  Also, I'd appreciate any make files or project files,
and any modifications you needed to make to get libpng to compile,
along with a #define variable to tell what compiler/system you are on.
If you needed to add transformations to libpng, or wish libpng would
provide the image in a different way, drop me a note (and code, if
possible), so I can consider supporting the transformation.
Finally, if you get any warning messages when compiling libpng
(note: not zlib), and they are easy to fix, I'd appreciate the
fix.  Please mention "libpng" somewhere in the subject line.  Thanks.

This release was created and will be supported by myself (of course
based in a large way on Guy's and Andreas' earlier work), and the PNG group.

Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit
https://lists.sourceforge.net/lists/listinfo/png-mng-implement
to subscribe) or to glennrp at users.sourceforge.net

You can't reach Guy, the original libpng author, at the addresses
given in previous versions of this document.  He and Andreas will read mail
addressed to the png-mng-implement list, however.

Please do not send general questions about PNG.  Send them to
the (png-mng-misc at lists.sourceforge.net, subscription required, visit
https://lists.sourceforge.net/lists/listinfo/png-mng-implement to subscribe)
On the other hand,
please do not send libpng questions to that address, send them to me
or to the png-mng-implement list.  I'll
get them in the end anyway.  If you have a question about something
in the PNG specification that is related to using libpng, send it
to me.  Send me any questions that start with "I was using libpng,
and ...".  If in doubt, send questions to me.  I'll bounce them
to others, if necessary.

Please do not send suggestions on how to change PNG.  We have
been discussing PNG for twelve years now, and it is official and
finished.  If you have suggestions for libpng, however, I'll
gladly listen.  Even if your suggestion is not used immediately,
it may be used later.

Files in this distribution:

      ANNOUNCE      =>  Announcement of this version, with recent changes
      CHANGES       =>  Description of changes between libpng versions
      KNOWNBUG      =>  List of known bugs and deficiencies
      LICENSE       =>  License to use and redistribute libpng
      README        =>  This file
      TODO          =>  Things not implemented in the current library
      Y2KINFO       =>  Statement of Y2K compliance
      example.c     =>  Example code for using libpng functions
      libpng-*-*-diff.txt => Diff from previous release
      libpng.3      =>  manual page for libpng (includes libpng.txt)
      libpng.txt    =>  Description of libpng and its functions
      libpngpf.3    =>  manual page for libpng's private functions
      png.5         =>  manual page for the PNG format
      png.c         =>  Basic interface functions common to library
      png.h         =>  Library function and interface declarations
      pngconf.h     =>  System specific library configuration
      pngerror.c    =>  Error/warning message I/O functions
      pngget.c      =>  Functions for retrieving info from struct
      pngmem.c      =>  Memory handling functions
      pngbar.png    =>  PNG logo, 88x31
      pngnow.png    =>  PNG logo, 98x31
      pngpread.c    =>  Progressive reading functions
      pngread.c     =>  Read data/helper high-level functions
      pngrio.c      =>  Lowest-level data read I/O functions
      pngrtran.c    =>  Read data transformation functions
      pngrutil.c    =>  Read data utility functions
      pngset.c      =>  Functions for storing data into the info_struct
      pngtest.c     =>  Library test program
      pngtest.png   =>  Library test sample image
      pngtrans.c    =>  Common data transformation functions
      pngwio.c      =>  Lowest-level write I/O functions
      pngwrite.c    =>  High-level write functions
      pngwtran.c    =>  Write data transformations
      pngwutil.c    =>  Write utility functions
      contrib       =>  Contributions
       gregbook         =>  source code for PNG reading and writing, from
                            Greg Roelofs' "PNG: The Definitive Guide",
                            O'Reilly, 1999
       msvctest     =>  Builds and runs pngtest using a MSVC workspace
       pngminus     =>  Simple pnm2png and png2pnm programs
       pngsuite     =>  Test images
       visupng      =>  Contains a MSVC workspace for VisualPng
      projects      =>  Contains project files and workspaces for building DLL
       beos             =>  Contains a Beos workspace for building libpng
       c5builder        =>  Contains a Borland workspace for building libpng
                            and zlib
       visualc6         =>  Contains a Microsoft Visual C++ (MSVC) workspace
                            for building libpng and zlib
       netware.txt      =>  Contains instructions for downloading a set of
                            project files for building libpng and zlib on
                            Netware.
       wince.txt        =>  Contains instructions for downloading a Microsoft
                            Visual C++ (Windows CD Toolkit) workspace for
                            building libpng and zlib on WindowsCE
      scripts       =>  Directory containing scripts for building libpng:
       descrip.mms      =>  VMS makefile for MMS or MMK
       makefile.std     =>  Generic UNIX makefile (cc, creates static libpng.a)
       makefile.elf     =>  Linux/ELF makefile symbol versioning,
                            gcc, creates libpng12.so.0.1.2.34)
       makefile.linux   =>  Linux/ELF makefile
                            (gcc, creates libpng12.so.0.1.2.34)
       makefile.gcmmx   =>  Linux/ELF makefile
                            (gcc, creates libpng12.so.0.1.2.34,
                            uses assembler code tuned for Intel MMX platform)
       makefile.gcc     =>  Generic makefile (gcc, creates static libpng.a)
       makefile.knr     =>  Archaic UNIX Makefile that converts files with
                            ansi2knr (Requires ansi2knr.c from
                            ftp://ftp.cs.wisc.edu/ghost)
       makefile.aix     =>  AIX makefile
       makefile.cygwin  =>  Cygwin/gcc makefile
       makefile.darwin  =>  Darwin makefile
       makefile.dec     =>  DEC Alpha UNIX makefile
       makefile.freebsd =>  FreeBSD makefile
       makefile.hpgcc   =>  HPUX makefile using gcc
       makefile.hpux    =>  HPUX (10.20 and 11.00) makefile
       makefile.hp64    =>  HPUX (10.20 and 11.00) makefile, 64 bit
       makefile.ibmc    =>  IBM C/C++ version 3.x for Win32 and OS/2 (static)
       makefile.intel   =>  Intel C/C++ version 4.0 and later
       libpng.icc       =>  Project file, IBM VisualAge/C++ 4.0 or later
       makefile.netbsd  =>  NetBSD/cc makefile, PNGGCCRD, makes libpng.so.
       makefile.ne12bsd  =>  NetBSD/cc makefile, PNGGCCRD, makes libpng12.so
       makefile.openbsd =>  OpenBSD makefile
       makefile.sgi     =>  Silicon Graphics IRIX (cc, creates static lib)
       makefile.sggcc   =>  Silicon Graphics
                            (gcc, creates libpng12.so.0.1.2.34)
       makefile.sunos   =>  Sun makefile
       makefile.solaris =>  Solaris 2.X makefile
                            (gcc, creates libpng12.so.0.1.2.34)
       makefile.so9     =>  Solaris 9 makefile
                            (gcc, creates libpng12.so.0.1.2.34)
       makefile.32sunu  =>  Sun Ultra 32-bit makefile
       makefile.64sunu  =>  Sun Ultra 64-bit makefile
       makefile.sco     =>  For SCO OSr5  ELF and Unixware 7 with Native cc
       makefile.mips    =>  MIPS makefile
       makefile.acorn   =>  Acorn makefile
       makefile.amiga   =>  Amiga makefile
       smakefile.ppc    =>  AMIGA smakefile for SAS C V6.58/7.00 PPC
                            compiler (Requires SCOPTIONS, copied from
                            scripts/SCOPTIONS.ppc)
       makefile.atari   =>  Atari makefile
       makefile.beos    =>  BEOS makefile for X86
       makefile.bor     =>  Borland makefile (uses bcc)
       makefile.bc32    =>  32-bit Borland C++ (all modules compiled in C mode)
       makefile.tc3     =>  Turbo C 3.0 makefile
       makefile.dj2     =>  DJGPP 2 makefile
       makefile.msc     =>  Microsoft C makefile
       makefile.vcawin32=>  makefile for Microsoft Visual C++ 5.0 and
                            later (uses assembler code tuned for Intel MMX
                            platform)
       makefile.vcwin32 =>  makefile for Microsoft Visual C++ 4.0 and
                            later (does not use assembler code)
       makefile.os2     =>  OS/2 Makefile (gcc and emx, requires pngos2.def)
       pngos2.def       =>  OS/2 module definition file used by makefile.os2
       makefile.watcom  =>  Watcom 10a+ Makefile, 32-bit flat memory model
       makevms.com      =>  VMS build script
       SCOPTIONS.ppc    =>  Used with smakefile.ppc

Good luck, and happy coding.

-Glenn Randers-Pehrson (current maintainer)
 Internet: glennrp at users.sourceforge.net

-Andreas Eric Dilger (former maintainer, 1996-1997)
 Internet: adilger at enel.ucalgary.ca
 Web: http://members.shaw.ca/adilger/

-Guy Eric Schalnat (original author and former maintainer, 1995-1996)
 (formerly of Group 42, Inc)
 Internet: gschal at infinet.com
Commit	Line	Data
	1	README for libpng version 1.2.34 - December 18, 2008 (shared library 12.0)
	2	See the note about version numbers near the top of png.h
	3
	4	See INSTALL for instructions on how to install libpng.
	5
	6	Libpng comes in several distribution formats. Get libpng-*.tar.gz,
	7	libpng-.tar.lzma, or libpng-.tar.bz2 if you want UNIX-style line
	8	endings in the text files, or lpng.7z or lpng.zip if you want DOS-style
	9	line endings. You can get UNIX-style line endings from the *.zip file
	10	by using "unzip -a" but there seems to be no simple way to recover
	11	UNIX-style line endings from the .7z file. The .tar.lzma file is
	12	recommended for *NIX users instead.
	13
	14	Version 0.89 was the first official release of libpng. Don't let the
	15	fact that it's the first release fool you. The libpng library has been in
	16	extensive use and testing since mid-1995. By late 1997 it had
	17	finally gotten to the stage where there hadn't been significant
	18	changes to the API in some time, and people have a bad feeling about
	19	libraries with versions < 1.0. Version 1.0.0 was released in
	20	March 1998.
	21
	22	****
	23	Note that some of the changes to the png_info structure render this
	24	version of the library binary incompatible with libpng-0.89 or
	25	earlier versions if you are using a shared library. The type of the
	26	"filler" parameter for png_set_filler() has changed from png_byte to
	27	png_uint_32, which will affect shared-library applications that use
	28	this function.
	29
	30	To avoid problems with changes to the internals of png_info_struct,
	31	new APIs have been made available in 0.95 to avoid direct application
	32	access to info_ptr. These functions are the png_set_<chunk> and
	33	png_get_<chunk> functions. These functions should be used when
	34	accessing/storing the info_struct data, rather than manipulating it
	35	directly, to avoid such problems in the future.
	36
	37	It is important to note that the APIs do not make current programs
	38	that access the info struct directly incompatible with the new
	39	library. However, it is strongly suggested that new programs use
	40	the new APIs (as shown in example.c and pngtest.c), and older programs
	41	be converted to the new format, to facilitate upgrades in the future.
	42	****
	43
	44	Additions since 0.90 include the ability to compile libpng as a
	45	Windows DLL, and new APIs for accessing data in the info struct.
	46	Experimental functions include the ability to set weighting and cost
	47	factors for row filter selection, direct reads of integers from buffers
	48	on big-endian processors that support misaligned data access, faster
	49	methods of doing alpha composition, and more accurate 16->8 bit color
	50	conversion.
	51
	52	The additions since 0.89 include the ability to read from a PNG stream
	53	which has had some (or all) of the signature bytes read by the calling
	54	application. This also allows the reading of embedded PNG streams that
	55	do not have the PNG file signature. As well, it is now possible to set
	56	the library action on the detection of chunk CRC errors. It is possible
	57	to set different actions based on whether the CRC error occurred in a
	58	critical or an ancillary chunk.
	59
	60	The changes made to the library, and bugs fixed are based on discussions
	61	on the png-mng-implement mailing list
	62	and not on material submitted privately to Guy, Andreas, or Glenn. They will
	63	forward any good suggestions to the list.
	64
	65	For a detailed description on using libpng, read libpng.txt. For
	66	examples of libpng in a program, see example.c and pngtest.c. For usage
	67	information and restrictions (what little they are) on libpng, see
	68	png.h. For a description on using zlib (the compression library used by
	69	libpng) and zlib's restrictions, see zlib.h
	70
	71	I have included a general makefile, as well as several machine and
	72	compiler specific ones, but you may have to modify one for your own needs.
	73
	74	You should use zlib 1.0.4 or later to run this, but it MAY work with
	75	versions as old as zlib 0.95. Even so, there are bugs in older zlib
	76	versions which can cause the output of invalid compression streams for
	77	some images. You will definitely need zlib 1.0.4 or later if you are
	78	taking advantage of the MS-DOS "far" structure allocation for the small
	79	and medium memory models. You should also note that zlib is a
	80	compression library that is useful for more things than just PNG files.
	81	You can use zlib as a drop-in replacement for fread() and fwrite() if
	82	you are so inclined.
	83
	84	zlib should be available at the same place that libpng is, or at
	85	ftp://ftp.simplesystems.org/pub/png/src/
	86
	87	You may also want a copy of the PNG specification. It is available
	88	as an RFC, a W3C Recommendation, and an ISO/IEC Standard. You can find
	89	these at http://www.libpng.org/pub/png/pngdocs.html
	90
	91	This code is currently being archived at libpng.sf.net in the
	92	[DOWNLOAD] area, and on CompuServe, Lib 20 (PNG SUPPORT)
	93	at GO GRAPHSUP. If you can't find it in any of those places,
	94	e-mail me, and I'll help you find it.
	95
	96	If you have any code changes, requests, problems, etc., please e-mail
	97	them to me. Also, I'd appreciate any make files or project files,
	98	and any modifications you needed to make to get libpng to compile,
	99	along with a #define variable to tell what compiler/system you are on.
	100	If you needed to add transformations to libpng, or wish libpng would
	101	provide the image in a different way, drop me a note (and code, if
	102	possible), so I can consider supporting the transformation.
	103	Finally, if you get any warning messages when compiling libpng
	104	(note: not zlib), and they are easy to fix, I'd appreciate the
	105	fix. Please mention "libpng" somewhere in the subject line. Thanks.
	106
	107	This release was created and will be supported by myself (of course
	108	based in a large way on Guy's and Andreas' earlier work), and the PNG group.
	109
	110	Send comments/corrections/commendations to png-mng-implement at lists.sf.net
	111	(subscription required; visit
	112	https://lists.sourceforge.net/lists/listinfo/png-mng-implement
	113	to subscribe) or to glennrp at users.sourceforge.net
	114
	115	You can't reach Guy, the original libpng author, at the addresses
	116	given in previous versions of this document. He and Andreas will read mail
	117	addressed to the png-mng-implement list, however.
	118
	119	Please do not send general questions about PNG. Send them to
	120	the (png-mng-misc at lists.sourceforge.net, subscription required, visit
	121	https://lists.sourceforge.net/lists/listinfo/png-mng-implement to subscribe)
	122	On the other hand,
	123	please do not send libpng questions to that address, send them to me
	124	or to the png-mng-implement list. I'll
	125	get them in the end anyway. If you have a question about something
	126	in the PNG specification that is related to using libpng, send it
	127	to me. Send me any questions that start with "I was using libpng,
	128	and ...". If in doubt, send questions to me. I'll bounce them
	129	to others, if necessary.
	130
	131	Please do not send suggestions on how to change PNG. We have
	132	been discussing PNG for twelve years now, and it is official and
	133	finished. If you have suggestions for libpng, however, I'll
	134	gladly listen. Even if your suggestion is not used immediately,
	135	it may be used later.
	136
	137	Files in this distribution:
	138
	139	ANNOUNCE => Announcement of this version, with recent changes
	140	CHANGES => Description of changes between libpng versions
	141	KNOWNBUG => List of known bugs and deficiencies
	142	LICENSE => License to use and redistribute libpng
	143	README => This file
	144	TODO => Things not implemented in the current library
	145	Y2KINFO => Statement of Y2K compliance
	146	example.c => Example code for using libpng functions
	147	libpng---diff.txt => Diff from previous release
	148	libpng.3 => manual page for libpng (includes libpng.txt)
	149	libpng.txt => Description of libpng and its functions
	150	libpngpf.3 => manual page for libpng's private functions
	151	png.5 => manual page for the PNG format
	152	png.c => Basic interface functions common to library
	153	png.h => Library function and interface declarations
	154	pngconf.h => System specific library configuration
	155	pngerror.c => Error/warning message I/O functions
	156	pngget.c => Functions for retrieving info from struct
	157	pngmem.c => Memory handling functions
	158	pngbar.png => PNG logo, 88x31
	159	pngnow.png => PNG logo, 98x31
	160	pngpread.c => Progressive reading functions
	161	pngread.c => Read data/helper high-level functions
	162	pngrio.c => Lowest-level data read I/O functions
	163	pngrtran.c => Read data transformation functions
	164	pngrutil.c => Read data utility functions
	165	pngset.c => Functions for storing data into the info_struct
	166	pngtest.c => Library test program
	167	pngtest.png => Library test sample image
	168	pngtrans.c => Common data transformation functions
	169	pngwio.c => Lowest-level write I/O functions
	170	pngwrite.c => High-level write functions
	171	pngwtran.c => Write data transformations
	172	pngwutil.c => Write utility functions
	173	contrib => Contributions
	174	gregbook => source code for PNG reading and writing, from
	175	Greg Roelofs' "PNG: The Definitive Guide",
	176	O'Reilly, 1999
	177	msvctest => Builds and runs pngtest using a MSVC workspace
	178	pngminus => Simple pnm2png and png2pnm programs
	179	pngsuite => Test images
	180	visupng => Contains a MSVC workspace for VisualPng
	181	projects => Contains project files and workspaces for building DLL
	182	beos => Contains a Beos workspace for building libpng
	183	c5builder => Contains a Borland workspace for building libpng
	184	and zlib
	185	visualc6 => Contains a Microsoft Visual C++ (MSVC) workspace
	186	for building libpng and zlib
	187	netware.txt => Contains instructions for downloading a set of
	188	project files for building libpng and zlib on
	189	Netware.
	190	wince.txt => Contains instructions for downloading a Microsoft
	191	Visual C++ (Windows CD Toolkit) workspace for
	192	building libpng and zlib on WindowsCE
	193	scripts => Directory containing scripts for building libpng:
	194	descrip.mms => VMS makefile for MMS or MMK
	195	makefile.std => Generic UNIX makefile (cc, creates static libpng.a)
	196	makefile.elf => Linux/ELF makefile symbol versioning,
	197	gcc, creates libpng12.so.0.1.2.34)
	198	makefile.linux => Linux/ELF makefile
	199	(gcc, creates libpng12.so.0.1.2.34)
	200	makefile.gcmmx => Linux/ELF makefile
	201	(gcc, creates libpng12.so.0.1.2.34,
	202	uses assembler code tuned for Intel MMX platform)
	203	makefile.gcc => Generic makefile (gcc, creates static libpng.a)
	204	makefile.knr => Archaic UNIX Makefile that converts files with
	205	ansi2knr (Requires ansi2knr.c from
	206	ftp://ftp.cs.wisc.edu/ghost)
	207	makefile.aix => AIX makefile
	208	makefile.cygwin => Cygwin/gcc makefile
	209	makefile.darwin => Darwin makefile
	210	makefile.dec => DEC Alpha UNIX makefile
	211	makefile.freebsd => FreeBSD makefile
	212	makefile.hpgcc => HPUX makefile using gcc
	213	makefile.hpux => HPUX (10.20 and 11.00) makefile
	214	makefile.hp64 => HPUX (10.20 and 11.00) makefile, 64 bit
	215	makefile.ibmc => IBM C/C++ version 3.x for Win32 and OS/2 (static)
	216	makefile.intel => Intel C/C++ version 4.0 and later
	217	libpng.icc => Project file, IBM VisualAge/C++ 4.0 or later
	218	makefile.netbsd => NetBSD/cc makefile, PNGGCCRD, makes libpng.so.
	219	makefile.ne12bsd => NetBSD/cc makefile, PNGGCCRD, makes libpng12.so
	220	makefile.openbsd => OpenBSD makefile
	221	makefile.sgi => Silicon Graphics IRIX (cc, creates static lib)
	222	makefile.sggcc => Silicon Graphics
	223	(gcc, creates libpng12.so.0.1.2.34)
	224	makefile.sunos => Sun makefile
	225	makefile.solaris => Solaris 2.X makefile
	226	(gcc, creates libpng12.so.0.1.2.34)
	227	makefile.so9 => Solaris 9 makefile
	228	(gcc, creates libpng12.so.0.1.2.34)
	229	makefile.32sunu => Sun Ultra 32-bit makefile
	230	makefile.64sunu => Sun Ultra 64-bit makefile
	231	makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc
	232	makefile.mips => MIPS makefile
	233	makefile.acorn => Acorn makefile
	234	makefile.amiga => Amiga makefile
	235	smakefile.ppc => AMIGA smakefile for SAS C V6.58/7.00 PPC
	236	compiler (Requires SCOPTIONS, copied from
	237	scripts/SCOPTIONS.ppc)
	238	makefile.atari => Atari makefile
	239	makefile.beos => BEOS makefile for X86
	240	makefile.bor => Borland makefile (uses bcc)
	241	makefile.bc32 => 32-bit Borland C++ (all modules compiled in C mode)
	242	makefile.tc3 => Turbo C 3.0 makefile
	243	makefile.dj2 => DJGPP 2 makefile
	244	makefile.msc => Microsoft C makefile
	245	makefile.vcawin32=> makefile for Microsoft Visual C++ 5.0 and
	246	later (uses assembler code tuned for Intel MMX
	247	platform)
	248	makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and
	249	later (does not use assembler code)
	250	makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def)
	251	pngos2.def => OS/2 module definition file used by makefile.os2
	252	makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model
	253	makevms.com => VMS build script
	254	SCOPTIONS.ppc => Used with smakefile.ppc
	255
	256	Good luck, and happy coding.
	257
	258	-Glenn Randers-Pehrson (current maintainer)
	259	Internet: glennrp at users.sourceforge.net
	260
	261	-Andreas Eric Dilger (former maintainer, 1996-1997)
	262	Internet: adilger at enel.ucalgary.ca
	263	Web: http://members.shaw.ca/adilger/
	264
	265	-Guy Eric Schalnat (original author and former maintainer, 1995-1996)
	266	(formerly of Group 42, Inc)
	267	Internet: gschal at infinet.com