\documentclass[a4paper,12pt,twoside]{article}
\usepackage[ngerman]{babel}
\include{setup}
\include{setup-builddir} % load \def\builddir{}

\def\tIngredients{Zutaten}
\def\tRecipe{Rezept}
\def\tPagePrefix{S.}

\begin{document}
\makefrontmatter
\graphicspath{{\builddir/de/}}
\include{\builddir/de/pdf-export}
\end{document}