Merge #22

22: Disable no_std when the std feature is present r=japaric a=dflemstr

This is for example needed when implementing the `std::error::Error` trait which is only possible if the `std` crate is available

Co-authored-by: David Flemström <dflemstr@spotify.com>

Author: bors[bot]

src/lib.rs

@@ -66,7 +66,7 @@
 #![deny(rust_2018_compatibility)]
 #![deny(rust_2018_idioms)]
 #![deny(warnings)]
-#![no_std]
+#![cfg_attr(not(feature = "std"), no_std)]
 
 pub mod de;
 pub mod ser;