Port #[export_name] to the new attribute parsing infrastructure

Signed-off-by: Jonathan Brouwer <jonathantbrouwer@gmail.com>

compiler/rustc_attr_parsing/src/context.rs

@@ -16,7 +16,7 @@ use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 
 use crate::attributes::allow_unstable::{AllowConstFnUnstableParser, AllowInternalUnstableParser};
 use crate::attributes::codegen_attrs::{
-    ColdParser, NakedParser, NoMangleParser, OptimizeParser, TrackCallerParser,
+    ColdParser, ExportNameParser, NakedParser, NoMangleParser, OptimizeParser, TrackCallerParser,
 };
 use crate::attributes::confusables::ConfusablesParser;
 use crate::attributes::deprecation::DeprecationParser;
@@ -117,6 +117,7 @@ attribute_parsers!(
         Single<ConstContinueParser>,
         Single<ConstStabilityIndirectParser>,
         Single<DeprecationParser>,
+        Single<ExportNameParser>,
         Single<InlineParser>,
         Single<LoopMatchParser>,
         Single<MayDangleParser>,