tests/pngstest-* are changed so that the new test files are divided into 8
groups by gamma and alpha channel.  This makes each test take just under 5
seconds on a moderately up-to-date x86_64 system using libpng16 (test times are
somewhat variable under libpng17 at present because of the lack of optimization
in some gamma processing paths.)

These tests have considerably better code and pixel-value coverage than
contrib/pngsuite however coverage is still incomplete.
Signed-off-by: NJohn Bowler <jbowler@acm.org>

pnglibconf.* in "make clean" (Cosmin).

configure.  In configure builds 'make install' changes/adds links like png.h
and libpng.a to point to the newly installed, versioned, files (e.g.
libpng17/png.h and libpng17.a). Three new configure options and some
rearrangement of Makefile.am allow creation of these links to be disabled.

it can manage, limited by the number of rows.

Use filter_neon_intrinsics.c in preference to filter_neon.S when possible.

arm/filter_neon_intrinsics.c; enable with configuration flag
PNG_ARM_NEON_INTRINSICS.

    1) Added the 'compile' program to the list of programs that must be cleaned
       in autogen.sh
    2) Added 'subdir-objects' which causes .c files in sub-directories to be
       compiled such that the corresponding .o files are also in the
       sub-directory.  This is because automake 1.14 warns that the
       current behavior of compiling to the top level directory may be removed
       in the future.
    3) Updated dependencies on pnglibconf.h to match the new .o locations and
       added all the files in contrib/libtests and contrib/tools that depend
       on pnglibconf.h
    4) Added 'BUILD_SOURCES = pnglibconf.h'; this is the automake recommended
       way of handling the dependencies of sources that are machine generated;
       unfortunately it only works if the user does 'make all' or 'make check',
       so the dependencies (3) are still required.

Added information in the documentation about problems with and fixes for
the bad CRC and bad iTXt chunk situations.

which requires both the correct libpng and the correct zlib to function
correctly.

For inflate, reverted previous fixes.
Added fixitxt and pngdeflate to the built programs and removed warnings
from the source code and timepng that are revealed as a result.  Fixed
fixitxt when the chunk length is more than 65535 (untested, no test case).

Revised scripts/makefile.freebsd to respect ZLIBDIR and ZLIBINC.

directory while building with a parallel make.

internal 'prefix.h' file can only be generated correctly after
pnglibconf.h, however the dependency was not in Makefile.am.  The
symptoms are unpredictable depending on the order make chooses to
build pngprefix.h and pnglibconf.h, often the error goes unnoticed
because there is a system pnglibconf.h to use instead.

code to the hardware subdirectory and added comments to pngrutil.c so that
implementors of other optimizations know what to do.

Added information about the new limits in the manual.

    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.

Renamed internal configure variable from prefix_TRUE to DO_PNG_PREFIX_TRUE

to be prefixed (suggested by Reuben Hawkins).  This is work in progress that
breaks some non-configure builds.

Added color-tests, silent-rules (Not yet implemented in Makefile.am) and
version checking to configure.ac

This version of autogen.sh attempts to dissuade people from running it when
it is not, or should not, be necessary.

Also some layout regularization and removal of introduced tab characters
(replaced with 3-character indentation).  Obsolete macros identified by
autoupdate have been removed; the replacements are all in 2.59 so
the pre-req hasn't been changed.  --enable-werror checks for support
for -Werror (or the given argument) in the compiler.  This mimics the
gcc configure option by allowing -Werror to be turned on safely; without
the option the tests written in configure itself fail compilation because
they cause compiler warnings.

separate.  The include path of 'config.h' was erroneously made relative in
pngvalid.c in libpng 1.5.7.