Auto merge of #55660 - alexcrichton:cleanup-alloc-system, r=dtolnay,SimonSapin

Remove the `alloc_system` crate

In what's hopefully one of the final nails in the coffin of the "old allocator story of yore" this PR deletes the `alloc_system` crate and all traces of it from the compiler. The compiler no longer needs to inject allocator crates anywhere and the `alloc_system` crate has no real reason to exist outside the standard library.

The unstable `alloc_system` crate is folded directly into the standard library where its stable interface, the `System` type, remains the same. All unstable traces of `alloc_system` are removed, however.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 0829593505d..f460d109c89 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -235,7 +235,6 @@
 #![cfg_attr(test, feature(test, update_panic_count))]
 #![feature(alloc)]
 #![feature(alloc_error_handler)]
-#![feature(alloc_system)]
 #![feature(allocator_api)]
 #![feature(allocator_internals)]
 #![feature(allow_internal_unsafe)]
@@ -316,7 +315,7 @@
 
 #[cfg(stage0)]
 #[global_allocator]
-static ALLOC: alloc_system::System = alloc_system::System;
+static ALLOC: alloc::System = alloc::System;
 
 // Explicitly import the prelude. The compiler uses this same unstable attribute
 // to import the prelude implicitly when building crates that depend on std.
@@ -337,7 +336,6 @@ pub use core::{unreachable, unimplemented, write, writeln, try};
 #[allow(unused_imports)] // macros from `alloc` are not used on all platforms
 #[macro_use]
 extern crate alloc as alloc_crate;
-extern crate alloc_system;
 #[doc(masked)]
 extern crate libc;