Stub out SSL_SESSION_get_max_early_data

This can theoretically be supported when `SSL_get_session` is
supported for client SSLs, as rustls has a public API for it.

Author: ctz

MATRIX.md

@@ -228,7 +228,7 @@
 | `SSL_SESSION_get_ex_data`  |  |  |  |  |
 | `SSL_SESSION_get_id`  |  | :white_check_mark: | :white_check_mark: | :white_check_mark: |
 | `SSL_SESSION_get_master_key`  |  |  | :white_check_mark: | :exclamation: [^stub] |
-| `SSL_SESSION_get_max_early_data`  |  |  | :white_check_mark: |  |
+| `SSL_SESSION_get_max_early_data`  |  |  | :white_check_mark: | :exclamation: [^stub] |
 | `SSL_SESSION_get_max_fragment_length`  |  |  |  |  |
 | `SSL_SESSION_get_protocol_version`  |  |  |  |  |
 | `SSL_SESSION_get_ticket_lifetime_hint`  |  |  |  |  |

build.rs

@@ -206,6 +206,7 @@ const ENTRYPOINTS: &[&str] = &[
     "SSL_SESSION_get_compress_id",
     "SSL_SESSION_get_id",
     "SSL_SESSION_get_master_key",
+    "SSL_SESSION_get_max_early_data",
     "SSL_SESSION_get_time",
     "SSL_SESSION_get_timeout",
     "SSL_session_reused",

src/entry.rs

@@ -2465,6 +2465,13 @@ entry_stub! {
     ) -> usize;
 }
 
+// This can be filled in when client SSL_SESSIONs are supported, via
+// `Tls13ClientSessionValue::max_early_data_size()`.
+
+entry_stub! {
+    pub fn _SSL_SESSION_get_max_early_data(_sess: *const SSL_SESSION) -> u32;
+}
+
 // ---------------------
 
 #[cfg(test)]