Fix cross-crate packed structs

Author: sanxiyn

src/librustc/metadata/encoder.rs

@@ -819,6 +819,7 @@ fn encode_info_for_item(ecx: @EncodeContext,
         }
 
         encode_name(ecx, ebml_w, item.ident);
+        encode_attributes(ebml_w, item.attrs);
         encode_path(ecx, ebml_w, path, ast_map::path_name(item.ident));
         encode_region_param(ecx, ebml_w, item);
 

src/test/auxiliary/packed.rs

@@ -0,0 +1,5 @@
+#[packed]
+struct S {
+    a: u8,
+    b: u32
+}

src/test/run-pass/packed-struct-size-xc.rs

@@ -0,0 +1,8 @@
+// xfail-fast
+// aux-build:packed.rs
+
+extern mod packed;
+
+fn main() {
+    assert_eq!(sys::size_of::<packed::S>(), 5);
+}