Tikz library ducks is not portable

[muzimuzhi]

Currently, when ducks is loaded as a tikz libray, it loads tikzlibraryducks.code.tex, which loads tikzducks.sty through \usepackage{tikzducks}. Since \usepackage is a LaTeX command, this makes the tikz library ducks unusable in other formats, hence not portable.

tikzducks/tikzlibraryducks.code.tex

Line 14 in d5ebc83

\usepackage{tikzducks}