\documentclass{article}
\usepackage{pdfpages}
%\VignetteIndexEntry{RcppClassic: Deprecated Rcpp API}
%\VignetteKeywords{R,Rcpp,API}
%\VignettePackage{RcppClassic}
%\VignetteEncoding{UTF-8}
\begin{document}
\includepdf[pages=-, fitpaper=true]{pdf/RcppClassic-intro.pdf}
\end{document}