diff -ur nginx-1.13.12-wolfssl/src/event/ngx_event_openssl.c nginx-1.13.12-wolfssl-debug/src/event/ngx_event_openssl.c
--- nginx-1.13.12-wolfssl/src/event/ngx_event_openssl.c	2018-04-18 09:38:23.587563895 +1000
+++ nginx-1.13.12-wolfssl-debug/src/event/ngx_event_openssl.c	2018-04-18 09:39:21.071751127 +1000
@@ -144,6 +144,11 @@
 
 #endif
 
+#ifdef WOLFSSL_NGINX
+    /* Turn on internal wolfssl debugging to stdout */
+    wolfSSL_Debugging_ON();
+#endif
+
 #if OPENSSL_VERSION_NUMBER >= 0x0090800fL
 #ifndef SSL_OP_NO_COMPRESSION
     {
Only in nginx-1.13.12-wolfssl-debug/src/event: ngx_event_openssl.c.orig