freeradius3: allow build without openssl engines

This applies a patch from upstream that avoids a call to ENGINE_cleanup
when the openssl library was built without engine support.

A workaround for a missing header check was used to silence a warning
about the implicit definition of RAND_load_file.  A proper fix has been
merged upstream as well.

Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>

net/freeradius3/patches/004-tls.c-allow-build-with-no-openssl-engine-support.patch

@@ -0,0 +1,24 @@
+From 0b17cf6e39064b008792811a6babf4cd75ac7744 Mon Sep 17 00:00:00 2001
+From: Eneas U de Queiroz <cote2004-github@yahoo.com>
+Date: Mon, 25 Feb 2019 10:48:48 -0300
+Subject: [PATCH] tls.c: allow build with no openssl engine support
+
+This avoids an ENGINE_cleanup call if openssl was compiled without
+engine support.
+
+Signed-off-by: Eneas U de Queiroz <cote2004-github@yahoo.com>
+
+diff --git a/src/main/tls.c b/src/main/tls.c
+index 73f0e3a3e8..9726953234 100644
+--- a/src/main/tls.c
++++ b/src/main/tls.c
+@@ -2743,7 +2743,9 @@ void tls_global_cleanup(void)
+ #elif OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
+ 	ERR_remove_thread_state(NULL);
+ #endif
++#ifndef OPENSSL_NO_ENGINE
+ 	ENGINE_cleanup();
++#endif
+ 	CONF_modules_unload(1);
+ 	ERR_free_strings();
+ 	EVP_cleanup();