Merge pull request 'prevent libcwtch.so fetch on build.rs so docs can build, be published' (#15) from docsrs into main

Reviewed-on: #15

build.rs

@@ -1,12 +1,15 @@
+use std::{env, io};
 use std::fs;
 use std::path::Path;
 use std::process::Command;
-use std::{env, io};
 
 use hex_literal::hex;
 use sha2::{Digest, Sha512};
 
 fn main() {
+    // Do not fetch lib on docs.rs as it cannot, build will fail, docs won't build
+    // https://docs.rs/about/builds
+    if std::env::var("DOCS_RS").is_err() {
         let out_dir = env::var_os("OUT_DIR").unwrap();
         println!("cargo:rustc-flags=-L {}", out_dir.to_str().unwrap());
         println!("cargo:rustc-link-lib=Cwtch");
@@ -30,4 +33,5 @@ fn main() {
         let hash_bytes = hasher.finalize();
 
         assert_eq!(hash_bytes[..], hex!("cb4368d72a46f8046261c50e6e9ecf170d8e606871d5de2c1e9e34303533c344f92f5d946d7e12614581dfa3ae8e638512af7f4623ed91b1ceb1570de14bf192")[..]);
+    }
 }