build: Fixing and suppressing all warnings

clang generates a number of harmless warnings originated from cryptopp
library.

Change-Id: I676e7b6d60588867f55a2ce1cd88ef263c3e38df
diff --git a/src/encoding/oid.cpp b/src/encoding/oid.cpp
index 0fb6697..c10a143 100644
--- a/src/encoding/oid.cpp
+++ b/src/encoding/oid.cpp
@@ -5,6 +5,19 @@
  * See COPYING for copyright and distribution information.
  */
 
+#if __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreorder"
+#pragma clang diagnostic ignored "-Wtautological-compare"
+#pragma clang diagnostic ignored "-Wunused-variable"
+#pragma clang diagnostic ignored "-Wunused-function"
+#elif __GNUC__
+#pragma GCC diagnostic ignored "-Wreorder"
+#pragma GCC diagnostic ignored "-Wtautological-compare"
+#pragma GCC diagnostic ignored "-Wunused-variable"
+#pragma GCC diagnostic ignored "-Wunused-function"
+#endif
+
 #include <stdlib.h>
 #include <sstream>