Minor fixes to o_p_test.c (CMakeLists.txt and includes)
diff --git a/programs/test/o_p_test.c b/programs/test/o_p_test.c
index 0665098..3a6c693 100644
--- a/programs/test/o_p_test.c
+++ b/programs/test/o_p_test.c
@@ -32,7 +32,9 @@
 #include <sys/stat.h>
 
 #include <openssl/rsa.h>
+#ifndef OPENSSL_NO_ENGINE
 #include <openssl/engine.h>
+#endif
 #include <openssl/pem.h>
 #include <openssl/bio.h>