I am running current~unstable Gentoo release. With the upgrade to media-libs/libpng-1.6.2 there wonderfully where automatic rebuilds of nearly all dependend builds :) Only in case of thunderbird there had to be issued revdep-rebuild -L /usr/lib64/libpng15.so.15 Reproducible: Always
Fixed in mozilla-overlay for firefox, seamonkey, and thunderbird. Won't be committed to the tree until there is another reason to revbump or version-bump, though.
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