[tex-live] dvipng 1.6 build, libraries

[Karl Berry]

    I just remembered that there was one libpng security
    issue in October last year, causing programs to crash:

Happily, it seems Martin has already updated libpng in the TL sources to
the current release, which fixes those infamous crashes (libpng 1.2.8).

I guess I will skip researching the other libs and hope for next year.

Thanks,
Karl