syntax: replace uses of old deriving attribute with new one

src/libsyntax/parse/parser.rs

@@ -93,7 +93,7 @@ use core::either;
 use core::vec;
 use std::oldmap::HashMap;
 
-#[deriving_eq]
+#[deriving(Eq)]
 enum restriction {
     UNRESTRICTED,
     RESTRICT_STMT_EXPR,