pngmeta: undefined symbols (doesn't build)

[macports@…]

pngmeta fails to build:

:info:build /usr/bin/gcc-4.2  -pipe -O2 -arch x86_64 -I/opt/local/include -I/opt/local/include -L/opt/local/lib -arch
 x86_64 -o pngmeta  pngmeta.o  -lpng -lz  -L/opt/local/include -L/opt/local/include -lpng -L/opt/local/lib -lm -L/opt
/local/lib:info:build Undefined symbols:
:info:build   "_png_handle_tIME", referenced from:
:info:build       _png_skip_till_end in pngmeta.o
:info:build   "_png_handle_tEXt", referenced from:
:info:build       _png_skip_till_end in pngmeta.o

(more undefined symbols follow, full build log attached)

[macports@…]

Failed build log

[jmroot (Joshua Root)]

As per the ticket guidelines, it's not useful to cc nomaintainer.

[ryandesign (Ryan Carsten Schmidt)]

You can read about this problem in the ​mailing list archives three years ago. Basically, we believe the pngmeta software is obsolete. We should probably remove the port.

[ryandesign (Ryan Carsten Schmidt)]

vinc17 pointed out in #28183 that pngmeta built fine with libpng 1.2.8, and I can confirm this even today by backdating the libpng port; pngmeta does not build with libpng 1.2.44 or 1.4.5. Perhaps this gives us a chance to bisect and identify the version of libpng 1.2.x that broke pngmeta, and then analyze its changelog and differences.

[ryandesign (Ryan Carsten Schmidt)]

From the mailing list discussion from October 2007 linked above, we see the issue was present with libpng 1.2.21 already.

[vinc17@…]

Adding -Wall confirms that functions like png_crc_finish() are no longer declared:

pngmeta.c:122: warning: implicit declaration of function ‘png_crc_finish’

It seems they (at least some of them) were never part of the official libpng API, so that they have been removed without notice from libpng. The pngmeta.c code still has:

#define PNG_INTERNAL

So, if pngmeta relied on libpng internals, I'm not surprised that it can no longer be built.

Note that Debian has a modified version of pngmeta.

[ak.ml@…]

Cc Me!

[Dmole (Tim)]

sudo port install exiv2

is the solution in case, like me, you are searching for an answer.

3 years and pngmeta is not removed yet, I guess it's a low priority thing but still.

[cooljeanius (Eric Gallager)]

Cc Me!

[ryandesign (Ryan Carsten Schmidt)]

In 969170ec8bd4a69da3358e6288a97edbf6043926/macports-ports (master):

pngmeta: Remove unbuildable port

There has not been a new release of pngmeta in over 20 years and it has
not been buildable in MacPorts for over 11 years.

Closes: #26263