[gcc r14-7820] gccrs: attribute: Add missing header guard

[Arthur Cohen]

https://gcc.gnu.org/g:00f79c773bc247830b29b6cef02d89337123c167

commit r14-7820-g00f79c773bc247830b29b6cef02d89337123c167
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Tue Jun 20 15:46:20 2023 +0200

    gccrs: attribute: Add missing header guard
    
    Missing header guard may cause infinitie include recursion.
    
    gcc/rust/ChangeLog:
    
            * util/rust-attributes.h (RUST_ATTRIBUTES_H): Add missing header
            guard.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/util/rust-attributes.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/gcc/rust/util/rust-attributes.h b/gcc/rust/util/rust-attributes.h
index 1259d140009..1989d41dd13 100644
--- a/gcc/rust/util/rust-attributes.h
+++ b/gcc/rust/util/rust-attributes.h
@@ -15,6 +15,8 @@
 // You should have received a copy of the GNU General Public License
 // along with GCC; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
+#ifndef RUST_ATTRIBUTES_H
+#define RUST_ATTRIBUTES_H
 
 #include "rust-ast.h"
 #include "rust-system.h"
@@ -267,3 +269,5 @@ private:
 
 } // namespace Analysis
 } // namespace Rust
+
+#endif /* ! RUST_ATTRIBUTES_H */