[gcc r15-8617] gccrs: attributes: Add #[derive] as a built-in attribute

[Arthur Cohen]

https://gcc.gnu.org/g:1d0be889267e3b3c58d97148640c0d46bc19253e

commit r15-8617-g1d0be889267e3b3c58d97148640c0d46bc19253e
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Fri Jan 3 15:45:57 2025 +0000

    gccrs: attributes: Add #[derive] as a built-in attribute
    
    gcc/rust/ChangeLog:
    
            * util/rust-attribute-values.h: Declare new attribute value.
            * util/rust-attributes.cc: Use it.

Diff:
---
 gcc/rust/util/rust-attribute-values.h | 1 +
 gcc/rust/util/rust-attributes.cc      | 1 +
 2 files changed, 2 insertions(+)

diff --git a/gcc/rust/util/rust-attribute-values.h b/gcc/rust/util/rust-attribute-values.h
index ef01e67dc528..9ef5cc52e81a 100644
--- a/gcc/rust/util/rust-attribute-values.h
+++ b/gcc/rust/util/rust-attribute-values.h
@@ -29,6 +29,7 @@ public:
   static constexpr auto &COLD = "cold";
   static constexpr auto &CFG = "cfg";
   static constexpr auto &CFG_ATTR = "cfg_attr";
+  static constexpr auto &DERIVE_ATTR = "derive";
   static constexpr auto &DEPRECATED = "deprecated";
   static constexpr auto &ALLOW = "allow";
   static constexpr auto &ALLOW_INTERNAL_UNSTABLE = "allow_internal_unstable";
diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index 9f63234112c5..03452c75bd8a 100644
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -46,6 +46,7 @@ static const BuiltinAttrDefinition __definitions[]
      {Attrs::COLD, CODE_GENERATION},
      {Attrs::CFG, EXPANSION},
      {Attrs::CFG_ATTR, EXPANSION},
+     {Attrs::DERIVE_ATTR, EXPANSION},
      {Attrs::DEPRECATED, STATIC_ANALYSIS},
      {Attrs::ALLOW, STATIC_ANALYSIS},
      {Attrs::ALLOW_INTERNAL_UNSTABLE, STATIC_ANALYSIS},