message: Include intrinsics from core::arch, not std::arch
diff: @@ -139,7 +139,7 @@ pub(crate) fn rem_digit(a: &BigUint, b: BigDigit) -> BigDigit {
  pub(crate) fn __add2(a: &mut [BigDigit], b: &[BigDigit]) -> BigDigit {
  debug_assert!(a.len() >= b.len());
  - use std::arch::x86_64::_addcarry_u64;
  + use core::arch::x86_64::_addcarry_u64;
  let mut carry = 0;
  let (a_lo, a_hi) = a.split_at_mut(b.len());
  @@ -205,7 +205,7 @@ pub(crate) fn add2(a: &mut [BigDigit], b: &[BigDigit]) {
  #[cfg(all(u64_digit, target_arch = "x86_64"))] // only run on x86_64, when we have u64 digits
  pub(crate) fn sub2(a: &mut [BigDigit], b: &[BigDigit]) {
  - use std::arch::x86_64::_subborrow_u64;
  + use core::arch::x86_64::_subborrow_u64;
  let mut borrow = 0;
  @@ -267,7 +267,7 @@ pub(crate) fn sub2(a: &mut [BigDigit], b: &[BigDigit]) {
  #[cfg(all(u64_digit, target_arch = "x86_64"))] // only run on x86_64, when we have u64 digits
  #[inline]
  pub(crate) fn __sub2rev(a: &[BigDigit], b: &mut [BigDigit]) -> BigDigit {
  - use std::arch::x86_64::_subborrow_u64;
  + use core::arch::x86_64::_subborrow_u64;
  debug_assert!(b.len() == a.len());
  let mut borrow = 0;
  