https://github.com/sfackler/rust-openssl/pull/2227

Index: vendor/openssl-sys-0.9.102/src/handwritten/x509.rs
--- vendor/openssl-sys-0.9.102/src/handwritten/x509.rs.orig
+++ vendor/openssl-sys-0.9.102/src/handwritten/x509.rs
@@ -1,10 +1,16 @@
 use super::super::*;
 use libc::*;
 
-#[repr(C)]
-pub struct X509_VAL {
-    pub notBefore: *mut ASN1_TIME,
-    pub notAfter: *mut ASN1_TIME,
+cfg_if! {
+    if #[cfg(libressl400)] {
+        pub enum X509_VAL {}
+    } else {
+        #[repr(C)]
+        pub struct X509_VAL {
+            pub notBefore: *mut ASN1_TIME,
+            pub notAfter: *mut ASN1_TIME,
+        }
+    }
 }
 
 pub enum X509_NAME_ENTRY {}
