mxcl/homebrew — pull request #21315 by rillian (2013-07-18 18:47:00+00:00)
Title: Update libpng source url to 1.6.3.

The only reason I install from source is to get libpng.pc which is
required by a lot of software these days. That's not included in
the older 1.5 releases, so there's no point keeping the stable base.