diff -Nru serf-1.3.9.orig/buckets/ssl_buckets.c serf-1.3.9/buckets/ssl_buckets.c
--- serf-1.3.9.orig/buckets/ssl_buckets.c	2016-06-30 17:45:07.000000000 +0200
+++ serf-1.3.9/buckets/ssl_buckets.c	2017-08-13 16:53:43.739050827 +0200
@@ -52,7 +52,8 @@
 #define APR_ARRAY_PUSH(ary,type) (*((type *)apr_array_push(ary)))
 #endif
 
-#if defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER >= 0x10100000L
+#if defined(OPENSSL_VERSION_NUMBER) && OPENSSL_VERSION_NUMBER >= 0x10100000L \
+    && !defined(LIBRESSL_VERSION_NUMBER)
 #define USE_OPENSSL_1_1_API
 #endif