png update -- breakage expected

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

I updated png to 1.2.9nb2 today.
This has broken some packages, since the default library name is
now libpng12.so and doesn't contain some symbols that were in
libpng.so (which still exists and does contain them).

If you note a broken package, please use send-pr(1), and I'll try
to fix it. I have a bulk build with png's dependencies running, so
I should find them myself too, given enough time :)

Sorry for the inconvenience.

Cheers,
 Thomas