rust-llvm: backport a fix for build with gcc-13

* needed for rust-llvm-native on hosts with gcc-13

Based on commit 3382759c ("llvm: backport a fix for build with gcc-13")

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>