std: Stablize the macros module

This commit performs a pass over the `std::macros` module, applying stability
attributes where necessary. In particular, this audits macros for patterns such
as:

* Standard use of forward-to-format-args via `$($arg:tt)*` (or `+`)
* Prevent macro-defined identifiers from leaking into expression arguments as
  hygiene is not perfectly implemented.
* Wherever possible, `$crate` is used now.

Specifically, the following actions were taken:

* The `std::macros` module itself is no longer public.
* The `panic!` macro is stable
* The `assert!` macro is stable
* The `assert_eq!` macro is stable
* The `debug_assert!` macro is stable
* The `debug_assert_eq!` macro is stable
* The `unreachable!` macro is stable after removing the extra forms to bring the
  definition in line with the `unimplemented!` macro.
* The `try!` macro is stable
* The `vec!` macro is stable

[breaking-change]

1 files changed, 0 insertions, 2 deletions

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index 9e14f9dd1ea..a9fc6df535e 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -81,7 +81,6 @@ pub mod ext {
     pub mod asm;
     pub mod base;
     pub mod build;
-    pub mod bytes;
     pub mod cfg;
     pub mod cfg_attr;
     pub mod concat;
@@ -89,7 +88,6 @@ pub mod ext {
     pub mod deriving;
     pub mod env;
     pub mod expand;
-    pub mod fmt;
     pub mod format;
     pub mod log_syntax;
     pub mod mtwt;