Add evmc and host interface implementation. Modify fuzzer harness to make use of evmc host/vm.

test/evmc/utils.h

@@ -0,0 +1,36 @@
+/* EVMC: Ethereum Client-VM Connector API.
+ * Copyright 2018-2019 The EVMC Authors.
+ * Licensed under the Apache License, Version 2.0.
+ */
+
+#pragma once
+
+/**
+ * @file
+ * A collection of helper macros to handle some non-portable features of C/C++ compilers.
+ *
+ * @addtogroup helpers
+ * @{
+ */
+
+/**
+ * @def EVMC_EXPORT
+ * Marks a function to be exported from a shared library.
+ */
+#if defined _MSC_VER || defined __MINGW32__
+#define EVMC_EXPORT __declspec(dllexport)
+#else
+#define EVMC_EXPORT __attribute__((visibility("default")))
+#endif
+
+/**
+ * @def EVMC_NOEXCEPT
+ * Safe way of marking a function with `noexcept` C++ specifier.
+ */
+#if __cplusplus
+#define EVMC_NOEXCEPT noexcept
+#else
+#define EVMC_NOEXCEPT
+#endif
+
+/** @} */