rust: proc-macro2: add SPDX License Identifiers

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

rust/proc-macro2/detection.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use core::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Once;
 

rust/proc-macro2/extra.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Items which do not have a correspondence to any API in the proc_macro crate,
 //! but are necessary to include in proc-macro2.
 

rust/proc-macro2/fallback.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(span_locations)]
 use crate::location::LineColumn;
 use crate::parse::{self, Cursor};

rust/proc-macro2/lib.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! [![github]](https://github.com/dtolnay/proc-macro2) [![crates-io]](https://crates.io/crates/proc-macro2) [![docs-rs]](crate)
 //!
 //! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github

rust/proc-macro2/location.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use core::cmp::Ordering;
 
 /// A line-column pair representing the start or end of a `Span`.

rust/proc-macro2/marker.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use alloc::rc::Rc;
 use core::marker::PhantomData;
 use core::panic::{RefUnwindSafe, UnwindSafe};

rust/proc-macro2/parse.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::fallback::{
     self, is_ident_continue, is_ident_start, Group, LexError, Literal, Span, TokenStream,
     TokenStreamBuilder,

rust/proc-macro2/rcvec.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use alloc::rc::Rc;
 use alloc::vec;
 use core::mem;

rust/proc-macro2/wrapper.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::detection::inside_proc_macro;
 #[cfg(span_locations)]
 use crate::location::LineColumn;