\documentclass{article}
\usepackage{pdfpages}
%\VignetteIndexEntry{Rcpp-extending}
%\VignetteKeywords{Rcpp, extending, R, Cpp}
%\VignettePackage{Rcpp}
%\VignetteEncoding{UTF-8}

\begin{document}
\includepdf[pages=-, fitpaper=true]{pdf/Rcpp-extending.pdf}
\end{document}