std: Remove the curious inner module

This isn't actually necessary any more with the advent of `$crate` and changes
in the compiler to expand macros to `::core::$foo` in the context of a
`#![no_std]` crate.

The libcore inner module was also trimmed down a bit to the bare bones.

src/libstd/lib.rs

@@ -421,27 +421,10 @@ pub mod __rand {
 // because rustdoc only looks for these modules at the crate level.
 include!("primitive_docs.rs");
 
-// A curious inner-module that's not exported that contains the binding
-// 'std' so that macro-expanded references to std::error and such
-// can be resolved within libstd.
-#[doc(hidden)]
+// The expansion of --test has a few references to `::std::$foo` so this module
+// is necessary to get things to compile.
+#[cfg(test)]
 mod std {
-    pub use sync; // used for select!()
-    pub use error; // used for try!()
-    pub use fmt; // used for any formatting strings
-    pub use option; // used for thread_local!{}
-    pub use rt; // used for panic!()
-    pub use vec; // used for vec![]
-    pub use cell; // used for tls!
-    pub use thread; // used for thread_local!
-    pub use marker;  // used for tls!
-
-    // The test runner calls ::std::env::args() but really wants realstd
-    #[cfg(test)] pub use realstd::env as env;
-    // The test runner requires std::slice::Vector, so re-export std::slice just for it.
-    //
-    // It is also used in vec![]
-    pub use slice;
-
-    pub use boxed; // used for vec![]
+    pub use option;
+    pub use realstd::env;
 }