Removed scripting cruft from scripts/makefile.mingw
Removed mention of now nonexistent files from scripts/README.txt

updated projects/visualc71 and removed scripts/makefile.cygwin.

  and callbacks.
Changed rules for generation of the various symbol files and added a new
  rule for a DEF file (which is also added to the distribution).
Updated the symbol file generation to stop it adding spurious spaces
  to EOL (coming from preprocessor macro expansion).  Added a facility
  to join tokens in the output and rewrite *.dfn to use this.

    for DEF file generation.

    PNG_CALLBACK added to make callback definitions uniform.  PNGAPI split
    into PNGCAPI (base C form), PNGAPI (exports) and PNGCBAPI (callbacks),
    and appropriate changes made to all files.  Cygwin builds re-hinged to
    allow procedure call standard changes and to remove the need for the DEF
    file (fixes build on Cygwin).

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in the Windows build but are disabled by default.

for symbols removed and added ordinal numbers to the Windows DEF file,
and corrected the duplicated ordinal numbers on CE symbols that are
commented out.

or expressions (i.e. a trailing ';' must always be added) and correct
the format statements in various png_debug messages.

and libpngpf.3

so it will compile when neither PNG_USER_CHUNK_MALLOC_MAX nor
PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED is defined.

and removed a redundant line from the copyright info in pngconf.h

from the source files, along with "#define PNG_EXPOSE_INTERNAL_STRUCTURES"
and "#define PNG_NO_PEDANTIC_WARNINGS" (John Bowler).
Also created new pngdebug.h and moved debug definitions there.

and setjmp usage has been improved.

with the help of "cppi".

to look like those in "man man"