x11-libs/qt-3.3.8b fails to build with libpng-1.4 because a patch is not being applied
 

x11-libs/qt-3.3.8b-r2 and -r1 (in the kde-sunset overlay) currently
fail to compile with libpng-1.4 because some structure fields in png.h
have gotten renamed.

Fortunately, in February a patch to fix this issue
(files/qt-3.3.8-libpng14.patch) was added to the overlay.

Unfortunately, even though the patch is there, the qt ebuilds in the
overlay don't apply it.

Please add epatch "${FILESDIR}/qt-3.3.8-libpng14.patch" to the qt:3 ebuilds.

-Alexandre Rostovtsev.