Merge #14

14: make the const-fn feature work in 1.31(-beta) r=japaric a=japaric



Co-authored-by: Jorge Aparicio <jorge@japaric.io>

Author: bors[bot]

CHANGELOG.md

@@ -5,6 +5,16 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+## [v0.2.4] - 2018-10-30
+
+### Added
+
+- Note in the documentation that `Mutex` is not memory safe in multi-core systems.
+
+### Changed
+
+- The `const-fn` feature can now be used on 1.31-beta and will also work on stable 1.31.
+
 ## [v0.2.3] - 2018-08-17
 
 ### Fixed

Cargo.toml

@@ -7,7 +7,10 @@ keywords = ["bare-metal", "register", "peripheral", "interrupt"]
 license = "MIT OR Apache-2.0"
 name = "bare-metal"
 repository = "https://github.com/japaric/bare-metal"
-version = "0.2.3"
+version = "0.2.4"
 
 [features]
-const-fn = []
+const-fn = []
+
+[build-dependencies]
+rustc_version = "0.2.3"

build.rs

@@ -0,0 +1,9 @@
+extern crate rustc_version;
+
+fn main() {
+    let vers = rustc_version::version().unwrap();
+
+    if vers.major == 1 && vers.minor < 31 {
+        println!("cargo:rustc-cfg=unstable_const_fn")
+    }
+}

src/lib.rs

@@ -3,7 +3,7 @@
 #![deny(missing_docs)]
 #![deny(warnings)]
 #![cfg_attr(
-    feature = "const-fn",
+    all(feature = "const-fn", unstable_const_fn),
     feature(const_fn)
 )]
 #![no_std]