Merge ref 'bfc046a4b8d6' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: bfc046a4b8d6b57db02540182466e989a9b0fb40
Filtered ref: f529e65

This merge was created using https://github.com/rust-lang/josh-sync.

Author: The rustc-josh-sync Cronjob Bot

compiler-builtins/Cargo.toml

@@ -19,6 +19,8 @@ links = "compiler-rt"
 bench = false
 doctest = false
 test = false
+# make sure this crate isn't included in public standard library docs
+doc = false
 
 [dependencies]
 core = { path = "../../core", optional = true }