If you set up your package using rstan_package_skeleton() before
version 1.2.1 of rstantools it may be necessary for you to call
this function yourself in order to pass R CMD check in R
>= 3.4. If you used rstan_package_skeleton() in rstantools version
1.2.1 or later then this has already been done automatically.
init_cpp(name, path)The name of your package as a string.
The path to the root directory for your package as a string. If not specified it is assumed that this is already the current working directory.
This function is only called for its side effect of writing the
necessary init.cpp file to the package's src/ directory.