libstd: set baseline stability levels.

Earlier commits have established a baseline of `experimental` stability
for all crates under the facade (so their contents are considered
experimental within libstd). Since `experimental` is `allow` by
default, we should use the same baseline stability for libstd itself.

This commit adds `experimental` tags to all of the modules defined in
`std`, and `unstable` to `std` itself.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libstd/collections/mod.rs b/src/libstd/collections/mod.rs
index 9e5288f9541..ccef1c0fd2a 100644
--- a/src/libstd/collections/mod.rs
+++ b/src/libstd/collections/mod.rs
@@ -12,6 +12,8 @@
  * Collection types.
  */
 
+#![experimental]
+
 pub use core_collections::{Collection, Mutable, Map, MutableMap};
 pub use core_collections::{Set, MutableSet, Deque};
 pub use core_collections::{Bitv, BitvSet, BTree, DList, EnumSet};