Within C++, one can set different compilation flags using:
// [[Rcpp::plugins(name)]]
List of the built-in plugins:
// built-in C++11 plugin
// [[Rcpp::plugins(cpp11)]]
// built-in C++11 plugin for older g++ compiler
// [[Rcpp::plugins(cpp0x)]]
// built-in C++14 plugin for C++14 standard
// [[Rcpp::plugins(cpp14)]]
// built-in C++1y plugin for C++14 and C++17 standard under development
// [[Rcpp::plugins(cpp1y)]]
// built-in OpenMP++11 plugin
// [[Rcpp::plugins(openmp)]]