Created attachment 294751 [details, diff] qt-gui-4.6-libpng-1.5.diff qt-gui-4.6 fails to build against libpng-1.5 qt-gui-4.7 already works with libpng-1.5, but does not build on all arches. Attached patch was taken from upstream git and tested on sparc-solaris prefix.
confirmed on alpha/ia64/sparc as well
Applied in qt-gui-4.6.3.ebuild, qt-gui-4.6.3-r2.ebuild