deref_addrof checks across external macro boundary

[oxalica]

The code below suggests [$(($x, stringify!(x)),)*] to change the macro, even though it is from another crate.

Playground (one crate)

macro_rules! m {
    ($($x:tt),*) => { &[$(($x, stringify!(x)),)*] };
}

pub fn f() -> [(i32, &'static str); 3] {
    *m![1, 2, 3]
}

Well, I don't think it should check across macro boundary no matter where it is from.

[flip1995]

Just needs a macro check.