message: Add `pthread_attr_getstack` shim
diff: @@ -18,6 +18,27 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
  let this = self.eval_context_mut();
  match link_name.as_str() {
  + // Querying system information
  + "pthread_attr_getstack" => {
  + // We don't support "pthread_attr_setstack", so we just pretend all stacks have the same values here.
  + let [attr_place, addr_place, size_place] =
  + this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  + this.deref_operand(attr_place)?;
  + let addr_place = this.deref_operand(addr_place)?;
  + let size_place = this.deref_operand(size_place)?;
  +
  + this.write_scalar(
  + Scalar::from_uint(STACK_ADDR, this.pointer_size()),
  + &addr_place.into(),
  + )?;
  + this.write_scalar(
  + Scalar::from_uint(STACK_SIZE, this.pointer_size()),
  + &size_place.into(),
  + )?;
  +
  + // Return success (`0`).
  + this.write_null(dest)?;
  + }
  _ => return Ok(EmulateByNameResult::NotSupported),
  }
  Ok(EmulateByNameResult::NeedsJumping)
  