rust: zerocopy-derive: add `README.md`

Originally, when the Rust upstream `alloc` standard library crate was
vendored in commit 057b8d257107 ("rust: adapt `alloc` crate to the
kernel"), a `README.md` file was added to explain the provenance and
licensing of the source files.

Thus do the same for the `zerocopy-derive` crate.

Cc: Joshua Liebow-Feeser <joshlf@google.com>
Cc: Jack Wrenn <jswrenn@google.com>
Link: https://patch.msgid.link/20260608141439.182634-17-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

diff --git a/rust/zerocopy-derive/README.md b/rust/zerocopy-derive/README.md
new file mode 100644 (file)
index 0000000..110f4a4
--- /dev/null
+++ b/rust/zerocopy-derive/README.md
@@ -0,0 +1,14 @@
+# `zerocopy-derive`
+
+These source files come from the Rust `zerocopy-derive` crate, version v0.8.50
+(released 2026-05-31), hosted in the <https://github.com/google/zerocopy>
+repository, licensed under "BSD-2-Clause OR Apache-2.0 OR MIT" and only
+modified to add the SPDX license identifiers and to remove the generation of
+non-ASCII identifiers.
+
+For copyright details, please see:
+
+    https://github.com/google/zerocopy/blob/v0.8.50/README.md?plain=1
+    https://github.com/google/zerocopy/blob/v0.8.50/LICENSE-BSD
+    https://github.com/google/zerocopy/blob/v0.8.50/LICENSE-APACHE
+    https://github.com/google/zerocopy/blob/v0.8.50/LICENSE-MIT