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A general description is here.
The deprecated legacy typedefs of ‘Sint’ and ‘Sfloat’ in header ‘R.h’ can be excluded by defining macro ‘NO_S_TYPEDEFS’ before including the header. This is defined when using ‘R CMD check --as-cran’ or by defining the environment variable ‘_R_NO_S_TYPEDEFS_’ to a true value when running ‘R CMD check’.
If these are excluded, ‘R.h’ no longer includes ‘limits.h’ nor ‘climits’.