In most of the legacy makefiles (with only a few notable exceptions
such as makefile.linux), the "install" targets have been broken since
libpng-1.5.0beta01. Specifically, the "install-shared" targets produced
incorrect library names, due to a missing symbol in the definition of
the LIBSOREL macro.
Rather than correcting this long-standing and long-untested error, we
decided to remove the support for "make install" altogether, from all
legacy makefiles. Further use of "make install", "make install-static"
or "make install-shared" will fail with an error message.
Going forward, the only tested and supported manners to install libpng
shall be the conventional build and install procedures driven by the
configure script or by the CMake file.
Considering that "-Wextra" is a more descriptive alternative to "-W",
and that "-Wundef" is a highly useful warning option that has been
available in ancient versions of gcc (version 2.x), we replace all
occurrences of "-W -Wall" with "-Wall -Wextra -Wundef".
Also clean up the makefiles.
Delete variables (ALIGN, ARCH, DOCS) and targets (writelock) that are
no longer necessary.
Reorder the object file lists alphabetically, consistently across all
makefiles and build scripts.
Apply other minor fixes.
Fixed point APIs are now supported throughout (no missing APIs).
Internal fixed point arithmetic support exists for all internal floating
point operations.
sCAL validates the floating point strings it is passed.
Safe, albeit rudimentary, Watcom support is provided by PNG_API_RULE==2
Two new APIs exist to get the number of passes without turning on the
PNG_INTERLACE transform and to get the number of rows in the current
pass.
A new test program, pngvalid.c, validates the gamma code.
Errors in the 16 bit gamma correction (overflows) have been corrected.
cHRM chunk testing is done consistently (previously the floating point
API bypassed it, because the test really didn't work on FP, now the test
is performed on the actual values to be stored in the PNG file so it
works in the FP case too.)
Most floating point APIs now simply call the fixed point APIs after
converting the values to the fixed point form used in the PNG file.
The standard headers no longer include zlib.h, which is currently only
required for pngstruct.h and can therefore be internal.
(Patches by John Bowler)
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.
to prevent warnings about direct access to png structs by libpng functions
while building libpng. They need to be tested, especially
those using compilers other than gcc.
