7.18.2.3 Limits of fastest minimum-width integer types
minimum values of fastest minimum-width signed integer types
INT_FASTN_MIN -(2N-1 - 1)
maximum values of fastest minimum-width signed integer types
INT_FASTN_MAX 2N-1 - 1
maximum values of fastest minimum-width unsigned integer types
UINT_FASTN_MAX 2N - 1