message: improve old comment
diff: @@ -463,10 +463,10 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  // Querying system information
  "pthread_attr_getstack" => {
  - // We don't support "pthread_attr_setstack", so we just pretend all stacks have the same values here.
  + // We don't support "pthread_attr_setstack", so we just pretend all stacks have the same values here. Hence we can mostly ignore the input `attr_place`.
  let [attr_place, addr_place, size_place] =
  this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  - this.deref_operand(attr_place)?;
  + let _attr_place = this.deref_operand(attr_place)?;
  let addr_place = this.deref_operand(addr_place)?;
  let size_place = this.deref_operand(size_place)?;
  