From 41dc39b6fdef0e1c3f3b9aac43d9f469bb268dac Mon Sep 17 00:00:00 2001
From: Paul Dicker <pitdicker@gmail.com>
Date: Sat, 12 May 2018 14:15:20 +0200
Subject: [PATCH 1/2] Ignore stdweb feature with emscripten

---
 src/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index bd7882cd33b..882ff73e0fd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -188,7 +188,7 @@
 #[cfg(feature="serde1")] extern crate serde;
 #[cfg(feature="serde1")] #[macro_use] extern crate serde_derive;
 
-#[cfg(all(target_arch = "wasm32", feature = "stdweb"))]
+#[cfg(all(target_arch="wasm32", not(target_os="emscripten"), feature="stdweb"))]
 #[macro_use]
 extern crate stdweb;
 

From 36b6cffc04a2becdc0eddf43974cc0b55d86f21e Mon Sep 17 00:00:00 2001
From: Paul Dicker <pitdicker@gmail.com>
Date: Sat, 12 May 2018 21:50:56 +0200
Subject: [PATCH 2/2] Add note about Emscripten OsRng source

---
 src/rngs/os.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/rngs/os.rs b/src/rngs/os.rs
index 75cee9073de..96b8d90f85b 100644
--- a/src/rngs/os.rs
+++ b/src/rngs/os.rs
@@ -37,8 +37,11 @@ use rand_core::{CryptoRng, RngCore, Error, impls};
 ///   otherwise from `/dev/urandom`.
 /// - macOS, iOS: calls `SecRandomCopyBytes`.
 /// - Windows: calls `RtlGenRandom`.
-/// - WASM: calls `window.crypto.getRandomValues` in browsers,
-///   and in Node.js `require("crypto").randomBytes`.
+/// - WASM (with `stdweb` feature): calls `window.crypto.getRandomValues` in
+///   browsers, and in Node.js `require("crypto").randomBytes`.
+/// - Emscripten: reads from emulated `/dev/urandom`, which maps to the same
+///   interfaces as `stdweb`, but falls back to the insecure `Math.random()` if
+///   unavailable.
 /// - OpenBSD: calls `getentropy(2)`.
 /// - FreeBSD: uses the `kern.arandom` `sysctl(2)` mib.
 /// - Fuchsia: calls `cprng_draw`.