Make _STACK opaque for LibreSSL >= 3.9.0

Author: botovq

openssl-sys/src/handwritten/stack.rs

@@ -3,6 +3,8 @@ use libc::*;
 cfg_if! {
     if #[cfg(ossl110)] {
         pub enum OPENSSL_STACK {}
+    } else if #[cfg(libressl390)] {
+        pub enum _STACK {}
     } else {
         #[repr(C)]
         pub struct _STACK {

openssl-sys/src/macros.rs

@@ -58,7 +58,7 @@ macro_rules! cfg_if {
 macro_rules! stack {
     ($t:ident) => {
         cfg_if! {
-            if #[cfg(ossl110)] {
+            if #[cfg(any(ossl110, libressl390))] {
                 pub enum $t {}
             } else {
                 #[repr(C)]