rustc: Support both meta tags and attributes for crate metadata

This is a transitional patch for converting from 'meta' to attributes.

Issue #487

src/comp/back/link.rs

@@ -249,6 +249,10 @@ mod write {
  *
  */
 iter crate_export_metas(&ast::crate c) -> @ast::meta_item {
+    for (ast::attribute attr in c.node.attrs) {
+        put @attr.node.value;
+    }
+
     for (@ast::crate_directive cdir in c.node.directives) {
         alt (cdir.node) {
             case (ast::cdir_meta(?v, ?mis)) {

src/lib/std.rc

@@ -1,7 +1,7 @@
-meta export (name = "std",
-             vers = "0.1",
-             uuid = "122bed0b-c19b-4b82-b0b7-7ae8aead7297",
-             url = "http://rust-lang.org/src/std");
+#[name = "std"];
+#[vers = "0.1"];
+#[uuid = "122bed0b-c19b-4b82-b0b7-7ae8aead7297"];
+#[url = "http://rust-lang.org/src/std"];
 
 meta (comment = "Rust standard library",
       license = "BSD");