NO TALKING HERE. If you have a package failing, you should open a new bug and make it block this one.
You can use libpng-1.4.x to report bugs for this tracker by using following grep: egrep 'warning.*is deprecated.*/png\.h' <name of a build.log> Because those will be fatal errors in libpng 1.5.x now.
Minor note - matplotlib checks for libpng via 'pkg-config libpng'.
(In reply to comment #2) > Minor note - matplotlib checks for libpng via 'pkg-config libpng'. > Sorry, wrong bug.
Notes: the following packages use libpng but don't list it in their dependencies (might rely on transitive dependencies): app-text/calibre dev-python/pygame media-gfx/mypaint media-tv/xbmc sci-geosciences/mapserver x11-libs/libsvg-cairo x11-libs/wxGTK
Time to close this. Porting is over and remaining cruft[1] will be handled as needed. [1] pngcrush, optipng and tkimg