commit 403a3e2323be2109fdda00564953aabdd164bb79
Author: 李通洲 <carter.li@eoitek.com>
Date:   Thu Apr 5 15:50:51 2018 +0800

Use SSL_OP_PRIORITIZE_CHACHA when supported

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 88a6dbe..f79c394 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -330,6 +330,10 @@ ngx_ssl_create(ngx_ssl_t *ssl, ngx_uint_t protocols, void *data)
     }
 #endif
 
+#ifdef SSL_OP_PRIORITIZE_CHACHA
+    SSL_CTX_set_options(ssl->ctx, SSL_OP_PRIORITIZE_CHACHA);
+#endif
+
 #ifdef SSL_OP_NO_COMPRESSION
     SSL_CTX_set_options(ssl->ctx, SSL_OP_NO_COMPRESSION);
 #endif