SSL: initialization changes for OpenSSL 1.1.0.

OPENSSL_config() deprecated in OpenSSL 1.1.0.  Additionally,
SSL_library_init(), SSL_load_error_strings() and OpenSSL_add_all_algorithms()
are no longer available if OPENSSL_API_COMPAT is set to 0x10100000L.

The OPENSSL_init_ssl() function is now used instead with appropriate
arguments to trigger the same behaviour.  The configure test changed to
use SSL_CTX_set_options().

Deinitialization now happens automatically in OPENSSL_cleanup() called
via atexit(3), so we no longer call EVP_cleanup() and ENGINE_cleanup()
directly.
diff --git a/auto/lib/openssl/conf b/auto/lib/openssl/conf
index e438050..39d9602 100644
--- a/auto/lib/openssl/conf
+++ b/auto/lib/openssl/conf
@@ -52,7 +52,7 @@
         ngx_feature_incs="#include <openssl/ssl.h>"
         ngx_feature_path=
         ngx_feature_libs="-lssl -lcrypto $NGX_LIBDL"
-        ngx_feature_test="SSL_library_init()"
+        ngx_feature_test="SSL_CTX_set_options(NULL, 0)"
         . auto/feature
 
         if [ $ngx_found = no ]; then
diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 21c305f..9f3cc86 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -111,6 +111,12 @@
 ngx_int_t
 ngx_ssl_init(ngx_log_t *log)
 {
+#if OPENSSL_VERSION_NUMBER >= 0x10100003L
+
+    OPENSSL_init_ssl(OPENSSL_INIT_LOAD_CONFIG, NULL);
+
+#else
+
 #ifndef OPENSSL_IS_BORINGSSL
     OPENSSL_config(NULL);
 #endif
@@ -120,6 +126,8 @@
 
     OpenSSL_add_all_algorithms();
 
+#endif
+
 #if OPENSSL_VERSION_NUMBER >= 0x0090800fL
 #ifndef SSL_OP_NO_COMPRESSION
     {
@@ -3548,8 +3556,12 @@
 static void
 ngx_openssl_exit(ngx_cycle_t *cycle)
 {
+#if OPENSSL_VERSION_NUMBER < 0x10100003L
+
     EVP_cleanup();
 #ifndef OPENSSL_NO_ENGINE
     ENGINE_cleanup();
 #endif
+
+#endif
 }