Support @(link_section=<string>) for procedures

src/entity.cpp

@@ -249,6 +249,7 @@ struct Entity {
 			String  link_name;
 			String  link_prefix;
 			String  link_suffix;
+			String  link_section;
 			String  objc_selector_name;
 			Entity *objc_class;
 			DeferredProcedure deferred_procedure;