various: translation resources from cg backend

Extend `CodegenBackend` trait with a function returning the translation
resources from the codegen backend, which can be added to the complete
list of resources provided to the emitter.

Signed-off-by: David Wood <david.wood@huawei.com>

compiler/rustc_codegen_llvm/src/lib.rs

@@ -249,6 +249,10 @@ impl LlvmCodegenBackend {
 }
 
 impl CodegenBackend for LlvmCodegenBackend {
+    fn locale_resource(&self) -> &'static str {
+        crate::DEFAULT_LOCALE_RESOURCE
+    }
+
     fn init(&self, sess: &Session) {
         llvm_util::init(sess); // Make sure llvm is inited
     }