rust: zerocopy: add SPDX License Identifiers

Originally, when the Rust upstream `alloc` standard library crate was
vendored, the SPDX License Identifiers were added to every file so that
the license on those was clear. The same happened with the vendoring of
`proc_macro2`, `quote` and `syn`. Please see:

  commit 057b8d2571 ("rust: adapt `alloc` crate to the kernel")
  commit 69942c0a89 ("rust: syn: add SPDX License Identifiers")
  commit ddfa1b279d ("rust: quote: add SPDX License Identifiers")
  commit a9acfceb96 ("rust: proc-macro2: add SPDX License Identifiers")

Thus do the same for the `zerocopy` crate.

This makes `scripts/spdxcheck.py` pass: use parentheses like commit
06e9bfc1e5 ("ionic: make spdxcheck.py happy") did since we have two
`OR` operators in the expression (three licenses).

SPDX identifiers are not added to the `benches` files because they are
included in rendered documentation. Nevertheless, the `README.md` to be
added by a later commit mentions the license.

Finally, as requested, I filed an issue [1] with upstream about it.

Cc: Joshua Liebow-Feeser <joshlf@google.com>
Cc: Jack Wrenn <jswrenn@google.com>
Link: https://github.com/google/zerocopy/issues/3428 [1]
Link: https://patch.msgid.link/20260608141439.182634-10-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

rust/zerocopy/rustdoc/style.css

@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT */
+
 /*
 Copyright 2026 The Fuchsia Authors
 

rust/zerocopy/src/byte_slice.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/byteorder.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2019 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/deprecated.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/error.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/impls.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/layout.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/lib.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2018 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/macros.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/pointer/inner.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/pointer/invariant.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/pointer/mod.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2023 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/pointer/ptr.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2023 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/pointer/transmute.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2025 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/ref.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2024 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/split_at.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2025 The Fuchsia Authors
 //
 // Licensed under the 2-Clause BSD License <LICENSE-BSD or

rust/zerocopy/src/util/macro_util.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2022 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/util/macros.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2023 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/util/mod.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2023 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

rust/zerocopy/src/wrappers.rs

@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
+
 // Copyright 2023 The Fuchsia Authors
 //
 // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0