Add a feature to explicitly enable "std"

.travis.yml

@@ -10,6 +10,9 @@ matrix:
  - rust: stable
  env:
  - FEATURES='rayon'
+ - rust: stable
+ env:
+ - FEATURES='std'
  - rust: beta
  - rust: nightly
  env:

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "indexmap"
 edition = "2018"
-version = "1.5.1"
+version = "1.5.2"
 authors = [
 "bluss",
 "Josh Stone <cuviper@gmail.com>"
@@ -53,6 +53,9 @@ fxhash = "0.2.1"
 # Serialization with serde 1.0
 serde-1 = ["serde"]
 
+# Force the use of `std`, bypassing target detection.
+std = []
+
 # for testing only, of course
 test_low_transition_point = []
 test_debug = []

README.rst

@@ -66,6 +66,14 @@ which is roughly:
 Recent Changes
 ==============
 
+- 1.5.2
+
+ - The new "std" feature will force the use of ``std`` for users that explicitly
+ want the default ``S = RandomState``, bypassing the autodetection added in 1.3.0,
+ by @cuviper in PR 145_.
+
+.. _145: https://github.com/bluss/indexmap/pull/145
+
 - 1.5.1
 
  - Values can now be indexed by their ``usize`` position by @cuviper in PR 132_.

build.rs

@@ -1,5 +1,8 @@
 fn main() {
- let ac = autocfg::new();
- ac.emit_sysroot_crate("std");
+ // If "std" is explicitly requested, don't bother probing the target for it.
+ match std::env::var_os("CARGO_FEATURE_STD") {
+ Some(_) => autocfg::emit("has_std"),
+ None => autocfg::new().emit_sysroot_crate("std"),
+ }
  autocfg::rerun_path("build.rs");
 }