Update libtiff (perhaps major).
Merge branch 'vlada/libpng' into refs/top-bases/vlada/gtk3
Merge commit 'refs/top-bases/vlada/gtk3' into vlada/gtk3
make ghostscript work with new libtiff
Merge branch 'vlada/libpng' into refs/top-bases/vlada/gtk3
Merge commit 'refs/top-bases/vlada/gtk3' into vlada/gtk3