eth: fix warnings

Change-Id: I510df00599ea148fa18cec08a12737159c52ebd4

src/jamidht/eth/libdevcore/FixedHash.h

@@ -332,6 +332,9 @@ public:
                              ConstructFromHashType _t = FixedHash<T>::AlignLeft)
         : FixedHash<T>(_h, _t)
     {}
+    SecureFixedHash(SecureFixedHash<T> const& _h)
+        : FixedHash<T>(_h.makeInsecure())
+    {}
     template<unsigned M>
     explicit SecureFixedHash(SecureFixedHash<M> const& _h,
                              ConstructFromHashType _t = FixedHash<T>::AlignLeft)

src/jamidht/eth/libdevcrypto/Common.cpp

@@ -33,9 +33,11 @@ namespace {
 secp256k1_context const*
 getCtx()
 {
-    static std::unique_ptr<secp256k1_context, decltype(&secp256k1_context_destroy)>
-        s_ctx {secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY),
-               &secp256k1_context_destroy};
+    struct secp256k1Deleter {
+        void operator()(secp256k1_context* b) { secp256k1_context_destroy(b); }
+    };
+    static std::unique_ptr<secp256k1_context, secp256k1Deleter>
+        s_ctx(secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY));
     return s_ctx.get();
 }