The goal of pkgbuild is to make it easy to build packages with compiled code. It provides tools to configure your R session, and check that everything is working ok. If you are using RStudio, it also helps you trigger automatical install of the build tools.
You can install pkgbuild from github with:
# install.packages("devtools")
devtools::install_github("hadley/pkgbuild")
# Check that you have the build tools installed
pkgbuild::check_build_tools(debug = TRUE)
# Build a package
pkgbuild::build("/path/to/my/package")
# Run your own code in an environment guarnteed to
# have build tools available
pkgbuild::with_build_tools(my_code)