--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/go/go-system.h	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,148 @@
+// go-system.h -- Go frontend inclusion of gcc header files   -*- C++ -*-
+// Copyright (C) 2009-2017 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef GO_SYSTEM_H
+#define GO_SYSTEM_H
+
+#include "config.h"
+
+/* Define this so that inttypes.h defines the PRI?64 macros even
+   when compiling with a C++ compiler.  Define it here so in the
+   event inttypes.h gets pulled in by another header it is already
+   defined.  */
+#define __STDC_FORMAT_MACROS
+
+// These must be included before the #poison declarations in system.h.
+
+#include <algorithm>
+#include <string>
+#include <list>
+#include <map>
+#include <set>
+#include <vector>
+#include <sstream>
+
+#if defined(HAVE_UNORDERED_MAP)
+
+# include <unordered_map>
+# include <unordered_set>
+
+# define Unordered_map(KEYTYPE, VALTYPE) \
+	std::unordered_map<KEYTYPE, VALTYPE>
+
+# define Unordered_map_hash(KEYTYPE, VALTYPE, HASHFN, EQFN) \
+	std::unordered_map<KEYTYPE, VALTYPE, HASHFN, EQFN>
+
+# define Unordered_set(KEYTYPE) \
+	std::unordered_set<KEYTYPE>
+
+# define Unordered_set_hash(KEYTYPE, HASHFN, EQFN) \
+	std::unordered_set<KEYTYPE, HASHFN, EQFN>
+
+#elif defined(HAVE_TR1_UNORDERED_MAP)
+
+# include <tr1/unordered_map>
+# include <tr1/unordered_set>
+
+# define Unordered_map(KEYTYPE, VALTYPE) \
+	std::tr1::unordered_map<KEYTYPE, VALTYPE>
+
+# define Unordered_map_hash(KEYTYPE, VALTYPE, HASHFN, EQFN) \
+	std::tr1::unordered_map<KEYTYPE, VALTYPE, HASHFN, EQFN>
+
+# define Unordered_set(KEYTYPE) \
+	std::tr1::unordered_set<KEYTYPE>
+
+# define Unordered_set_hash(KEYTYPE, HASHFN, EQFN) \
+	std::tr1::unordered_set<KEYTYPE, HASHFN, EQFN>
+
+#elif defined(HAVE_EXT_HASH_MAP)
+
+# include <ext/hash_map>
+# include <ext/hash_set>
+
+# define Unordered_map(KEYTYPE, VALTYPE) \
+	__gnu_cxx::hash_map<KEYTYPE, VALTYPE>
+
+# define Unordered_map_hash(KEYTYPE, VALTYPE, HASHFN, EQFN) \
+	__gnu_cxx::hash_map<KEYTYPE, VALTYPE, HASHFN, EQFN>
+
+# define Unordered_set(KEYTYPE) \
+	__gnu_cxx::hash_set<KEYTYPE>
+
+# define Unordered_set_hash(KEYTYPE, HASHFN, EQFN) \
+	__gnu_cxx::hash_set<KEYTYPE, HASHFN, EQFN>
+
+// Provide hash functions for strings and pointers.
+
+namespace __gnu_cxx
+{
+
+template<>
+struct hash<std::string>
+{
+  size_t
+  operator()(std::string s) const
+  { return __stl_hash_string(s.c_str()); }
+};
+
+template<typename T>
+struct hash<T*>
+{
+  size_t
+  operator()(T* p) const
+  { return reinterpret_cast<size_t>(p); }
+};
+
+}
+
+#else
+
+# define Unordered_map(KEYTYPE, VALTYPE) \
+	std::map<KEYTYPE, VALTYPE>
+
+# define Unordered_set(KEYTYPE) \
+	std::set<KEYTYPE>
+
+// We could make this work by writing an adapter class which
+// implemented operator< in terms of the hash function.
+# error "requires hash table type"
+
+#endif
+
+// We don't really need iostream, but some versions of gmp.h include
+// it when compiled with C++, which means that we need to include it
+// before the macro magic of safe-ctype.h, which is included by
+// system.h.
+#include <iostream>
+
+#include "system.h"
+#include "ansidecl.h"
+#include "coretypes.h"
+
+#include "diagnostic-core.h"	/* For error_at and friends.  */
+#include "intl.h"		/* For _().  */
+
+// When using gcc, go_assert is just gcc_assert.
+#define go_assert(EXPR) gcc_assert(EXPR)
+
+// When using gcc, go_unreachable is just gcc_unreachable.
+#define go_unreachable() gcc_unreachable()
+
+#endif // !defined(GO_SYSTEM_H)