From dec68197011959f5423bd004158a5a61385dcff5 Mon Sep 17 00:00:00 2001
From: Ciprian Dorin Craciun <ciprian.craciun@gmail.com>
Date: Sat, 19 May 2018 23:49:13 +0300
Subject: [PATCH] Gracefully fail if `use_std` is not used

Use `compile_error!` macro to issue a meaningful compile error if the `use_std` feature is not enabled.
---
 src/lib.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 9f3577fffc..559cb51ef0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -521,6 +521,11 @@ another matching engine with fixed memory requirements.
 #![cfg_attr(test, deny(warnings))]
 #![cfg_attr(feature = "pattern", feature(pattern))]
 
+
+#[cfg(not(feature = "use_std"))]
+compile_error!("`use_std` feature is currently required to build this crate");
+
+
 extern crate aho_corasick;
 extern crate memchr;
 extern crate thread_local;