diff --git a/systest/build.rs b/systest/build.rs
index e8bd221d..8ff03c87 100644
--- a/systest/build.rs
+++ b/systest/build.rs
@@ -61,7 +61,8 @@ fn main() {
         .header("openssl/bn.h")
         .header("openssl/aes.h")
         .header("openssl/ocsp.h")
-        .header("openssl/evp.h");
+        .header("openssl/evp.h")
+        .header("openssl/x509_vfy.h");
 
     if openssl_version.is_some() {
         cfg.header("openssl/cms.h");