diff --git a/openssl-sys/build/find_vendored.rs b/openssl-sys/build/find_vendored.rs
index 11462a57bcc61788ca1aa3f9060dde8ff001eeda..bd5fbfb056cf0aef0904c3c588da4cf0b885d095 100644
--- a/openssl-sys/build/find_vendored.rs
+++ b/openssl-sys/build/find_vendored.rs
@@ -3,6 +3,7 @@ use std::path::PathBuf;
 
 pub fn get_openssl(_target: &str) -> (PathBuf, PathBuf) {
     let artifacts = openssl_src::Build::new().build();
+    println!("cargo:vendored=1");
     (
         artifacts.lib_dir().to_path_buf(),
         artifacts.include_dir().to_path_buf(),