Before I embark on updating gcc, has anyone actually attempted this, and can they confirm building R from source is required to update the gcc version one uses to compile c++ code with Rcpp (i.e. not necessarily for package authoring and certainly not for CRAN-valid packages)?
See Dirk's answer to this question, and the follow-on comment from the original poster How to use gcc 4.8.1 with Rcpp on Windows.