LuaLaTeX, TeXLive 2016, standalone: undefined control sequence

The fix is easy: add \RequirePackage{luatex85} as the very first line, a temporary workaround until standalone is updated. It should do no harm even after the update.

\RequirePackage{luatex85}
\documentclass{standalone}
\begin{document}
hi
\end{document}

The easiest way is to load luatex85 package. You probably will need to load it before documentclass, using RequirePackage

The longer story is that luatex now no longer defines many primitives with pdf prefix. The luatex85 package defines aliases of primitives which have the same names as in pdftex and earlier versions of luatex.