MDEV-17441 - InnoDB transition to C++11 atomics

Added Atomic_counter class to replace big set of atomic operations uses
in InnoDB, as well as in the server.

include/my_counter.h

+#ifndef MY_COUNTER_H_INCLUDED
+#define MY_COUNTER_H_INCLUDED
+/*
+   Copyright (C) 2018 MariaDB Foundation
+
+   This program 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; version 2 of the License.
+
+   This program 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 this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
+*/
+
+#include <atomic>
+
+
+template <typename Type> class Atomic_counter
+{
+  std::atomic<Type> m_counter;
+
+  Type add(Type i) { return m_counter.fetch_add(i, std::memory_order_relaxed); }
+  Type sub(Type i) { return m_counter.fetch_sub(i, std::memory_order_relaxed); }
+
+public:
+  Type operator++(int) { return add(1); }
+  Type operator--(int) { return sub(1); }
+
+  Type operator++() { return add(1) + 1; }
+  Type operator--() { return sub(1) - 1; }
+
+  Type operator+=(const Type i) { return add(i) + i; }
+  Type operator-=(const Type i) { return sub(i) - i; }
+
+  operator Type() const { return m_counter.load(std::memory_order_relaxed); }
+  Type operator=(const Type val)
+  { m_counter.store(val, std::memory_order_relaxed); return val; }
+};
+#endif /* MY_COUNTER_H_INCLUDED */