Function gmp_mpfr_sys::gmp::__gmpn_add_1

pub unsafe extern fn __gmpn_add_1(rp: *mut mp_limb_t,
                                  s1p: *const mp_limb_t,
                                  n: mp_size_t,
                                  s2limb: mp_limb_t)
                                  -> mp_limb_t