[master] Enabled iTXt support by default.

    To ensure binary compatibility with
    previous versions, the "lang" and "lang_key" members will be assumed
    to be omitted from previous versions unless the current libpng
    version was built with PNG_iTXt_SUPPORTED (which is otherwise no
    longer necessary to gain iTXt support), as a signal that the user has
    been building previous versions with PNG_iTXt_SUPPORTED as well.
5 files changed