and the png_free() of png_ptr->current_text from pngread.c

Added information about the new limits in the manual.

to reset the user limits to safe ones if PNG_SAFE_LIMITS is defined.
To enable, use CPPFLAGS=-DPNG_SAFE_LIMITS on the configure command
or put #define PNG_SAFE_LIMITS_SUPPORTED in pnglibconf.h.prebuilt.
(Reverted previous implementation of PNG_SECURE.)

to reset the user limits to safe ones if PNG_SECURE is defined.

    pngpread.c and use the sequential png_handle_tEXt, etc., in pngrutil.c;
    now that png_ptr->buffer is inaccessible to applications, the special
    handling is no longer useful.

one is found, issue a warning and increase png_ptr->num_palette accordingly.
Apps are responsible for checking to see if that happened.

    FLOATING_POINT options were switched off, png.h ended up with lone ';'
    characters.  This is not valid ANSI-C outside a function.  The ';'
    characters have been moved inside the definition of PNG_FP_EXPORT and
    PNG_FIXED_EXPORT. 2) If either option was switched off, the declaration
    of the corresponding functions were completely omitted, even though some
    of them are still used internally.  The result is still valid, but
    produces warnings from gcc with some warning options (including -Wall). The
    fix is to cause png.h to declare the functions with PNG_INTERNAL_FUNCTION
    when png.h is included from pngpriv.h.

Fixed a memory overwrite bug in simplified read of RGB PNG with
non-linear gamma Also bugs in the error checking in pngread.c and changed
quite a lot of the checks in pngstest.c to be correct; either correctly
written or not over-optimistic.  The pngstest changes are insufficient to
allow all possible RGB transforms to be passed; pngstest cmppixel needs
to be rewritten to make it clearer which errors it allows and then changed
to permit known inaccuracies.

The API is extremely inaccurate for sRGB conversions because it uses an 8-bit
intermediate linear value and it does not use the sRGB transform, so it
suffers from the known instability in gamma transforms for values close
to 0 (see Poynton).  The net result is that the calculation has a maximum
error of 14.99/255; 0.5/255^(1/2.2).  pngstest now uses 15 for the
permitted 8-bit error. This may still not be enough because of arithmetic
error.

projects/owatcom/pngstest.tgt

to libpng-1.6.0beta05 versions.

Renamed internal configure variable from prefix_TRUE to DO_PNG_PREFIX_TRUE

clone, not in a directory extracted from a tar distribution.

should not require itself.