Auto merge of rust-lang#3917 - RalfJung:sysroot, r=RalfJung

bump rustc-build-sysroot version

This removes an implicit `--cap-lints` in the sysroot build. Let's see if that causes any trouble for the targets we test.

Author: bors

cargo-miri/Cargo.lock

@@ -18,7 +18,7 @@ directories = "5"
 rustc_version = "0.4"
 serde_json = "1.0.40"
 cargo_metadata = "0.18.0"
-rustc-build-sysroot = "0.5.3"
+rustc-build-sysroot = "0.5.4"
 
 # Enable some feature flags that dev-dependencies need but dependencies
 # do not.  This makes `./miri install` after `./miri build` faster.