Add mstd_xxx headers to unit tests

Stripped down headers that route through to `std` forms more - eg
no local implementation of `atomic` or `mutex`.

Author: kjbracey

UNITTESTS/target_h/platform/cxxsupport/mstd_algorithm

@@ -0,0 +1,110 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2019 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MSTD_ALGORITHM_
+#define MSTD_ALGORITHM_
+
+/* <mstd_algorithm>
+ *
+ * - provides <algorithm>
+ * - For ARM C 5, standard C++11/14 features:
+ *   - std::min, std::max for std::initializer_list
+ *   - std::all_of, std::any_of, std::none_of
+ *   - std::find_if_not
+ *   - std::equal (2-range forms)
+ *   - std::copy_n, std::move, std::move_backward
+ *   - mstd::min, mstd::max constexpr replacements
+ */
+
+#include <algorithm>
+
+namespace mstd {
+using std::min;
+using std::max;
+using std::minmax;
+using std::initializer_list;
+using std::all_of;
+using std::any_of;
+using std::none_of;
+using std::for_each;
+using std::find;
+using std::find_if;
+using std::find_if_not;
+using std::find_end;
+using std::find_first_of;
+using std::adjacent_find;
+using std::count;
+using std::count_if;
+using std::mismatch;
+using std::equal;
+using std::search;
+using std::search_n;
+using std::copy;
+using std::copy_n;
+using std::copy_if;
+using std::move;
+using std::move_backward;
+using std::swap_ranges;
+using std::iter_swap;
+using std::transform;
+using std::replace;
+using std::replace_if;
+using std::replace_copy;
+using std::replace_copy_if;
+using std::fill;
+using std::fill_n;
+using std::generate;
+using std::generate_n;
+using std::remove;
+using std::remove_if;
+using std::remove_copy;
+using std::remove_copy_if;
+using std::unique;
+using std::unique_copy;
+using std::reverse;
+using std::reverse_copy;
+using std::rotate;
+using std::rotate_copy;
+using std::partition;
+using std::stable_partition;
+using std::sort;
+using std::stable_sort;
+using std::partial_sort;
+using std::partial_sort_copy;
+using std::nth_element;
+using std::lower_bound;
+using std::upper_bound;
+using std::equal_range;
+using std::binary_search;
+using std::merge;
+using std::inplace_merge;
+using std::includes;
+using std::set_union;
+using std::set_intersection;
+using std::set_difference;
+using std::set_symmetric_difference;
+using std::push_heap;
+using std::pop_heap;
+using std::make_heap;
+using std::sort_heap;
+using std::min_element;
+using std::max_element;
+using std::lexicographical_compare;
+using std::next_permutation;
+using std::prev_permutation;
+}
+
+#endif // MSTD_ALGORITHM_

UNITTESTS/target_h/platform/cxxsupport/mstd_atomic

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2017 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef MSTD_ATOMIC_
+#define MSTD_ATOMIC_
+
+#include <atomic>
+
+namespace mstd {
+using std::atomic;
+using std::atomic_is_lock_free;
+using std::atomic_store;
+using std::atomic_store_explicit;
+using std::atomic_load;
+using std::atomic_load_explicit;
+using std::atomic_exchange;
+using std::atomic_exchange_explicit;
+using std::atomic_compare_exchange_weak;
+using std::atomic_compare_exchange_weak_explicit;
+using std::atomic_compare_exchange_strong;
+using std::atomic_compare_exchange_strong_explicit;
+using std::atomic_fetch_add;
+using std::atomic_fetch_add_explicit;
+using std::atomic_fetch_sub;
+using std::atomic_fetch_sub_explicit;
+using std::atomic_fetch_and;
+using std::atomic_fetch_and_explicit;
+using std::atomic_fetch_or;
+using std::atomic_fetch_or_explicit;
+using std::atomic_fetch_xor;
+using std::atomic_fetch_xor_explicit;
+using std::atomic_flag;
+using std::atomic_flag_test_and_set;
+using std::atomic_flag_test_and_set_explicit;
+using std::atomic_flag_clear;
+using std::atomic_flag_clear_explicit;
+using std::atomic_init;
+using std::memory_order;
+using std::kill_dependency;
+using std::atomic_thread_fence;
+using std::atomic_signal_fence;
+}
+
+#endif

UNITTESTS/target_h/platform/cxxsupport/mstd_cstddef

@@ -0,0 +1,54 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2019 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MSTD_CSTDDEF_
+#define MSTD_CSTDDEF_
+
+/* <mstd_cstddef>
+ *
+ * - provides <cstddef>
+ * - For ARM C 5, standard C++11/14 features:
+ * - - adds macro replacements for alignof and alignas keywords
+ * - - adds missing std::nullptr_t
+ * - For all toolchains:
+ * - - MSTD_CONSTEXPR_XX_14 macros that can be used to mark
+ *     things that are valid as constexpr only for C++14 or later,
+ *     permitting constexpr use where ARM C 5 would reject it.
+ */
+
+#include <cstddef>
+
+/* Macros that can be used to mark functions and objects that are
+ * constexpr in C++14 or later, but not in earlier versions.
+ */
+#if __cplusplus >= 201402
+#define MSTD_CONSTEXPR_FN_14 constexpr
+#define MSTD_CONSTEXPR_OBJ_14 constexpr
+#else
+#define MSTD_CONSTEXPR_FN_14 inline
+#define MSTD_CONSTEXPR_OBJ_14 const
+#endif
+
+namespace mstd
+{
+using std::size_t;
+using std::ptrdiff_t;
+using std::nullptr_t;
+using std::max_align_t;
+
+}
+
+#endif // MSTD_CSTDDEF_

UNITTESTS/target_h/platform/cxxsupport/mstd_functional

@@ -0,0 +1,125 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2019 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under tUNChe License.
+ */
+#ifndef MSTD_FUNCTIONAL_
+#define MSTD_FUNCTIONAL_
+
+/* <mstd_functional>
+ *
+ * - includes toolchain's <functional>
+ * - For ARM C 5, standard C++11/14 features:
+ *   - std::mem_fn,
+ *   - std::reference_wrapper, std::ref, std::cref
+ *   - transparent std::plus<> etc
+ *   - std::bit_and, std::bit_or, std::bit_xor, std::bit_not
+ * - For all toolchains, C++17/20 backports:
+ *   - mbed::not_fn (C++17)
+ *   - mbed::invoke (C++17)
+ */
+
+#include <functional>
+
+#include <mstd_memory> // addressof
+#include <mstd_utility> // forward
+#include <mstd_type_traits>
+
+namespace mstd {
+
+// [func.invoke]
+#if __cpp_lib_invoke >= 201411
+using std::invoke;
+#else
+template <typename F, typename... Args>
+invoke_result_t<F, Args...> invoke(F&& f, Args&&... args)
+{
+    return impl::INVOKE(std::forward<F>(f), std::forward<Args>(args)...);
+}
+#endif // __cpp_lib_invoke
+
+} // namespace mstd
+
+namespace mstd {
+using std::reference_wrapper;
+using std::ref;
+using std::cref;
+using std::plus;
+using std::minus;
+using std::multiplies;
+using std::divides;
+using std::modulus;
+using std::negate;
+using std::equal_to;
+using std::not_equal_to;
+using std::greater;
+using std::less;
+using std::greater_equal;
+using std::less_equal;
+using std::logical_and;
+using std::logical_or;
+using std::logical_not;
+using std::bit_and;
+using std::bit_or;
+using std::bit_xor;
+using std::bit_not;
+
+#if __cpp_lib_not_fn >= 201603
+using std::not_fn;
+#else
+namespace impl {
+// [func.not_fn]
+template <typename F>
+class not_fn_t {
+    std::decay_t<F> fn;
+public:
+    explicit not_fn_t(F&& f) : fn(std::forward<F>(f)) { }
+    not_fn_t(const not_fn_t &other) = default;
+    not_fn_t(not_fn_t &&other) = default;
+
+    template<typename... Args>
+    auto operator()(Args&&... args) & -> decltype(!std::declval<invoke_result_t<std::decay_t<F> &, Args...>>())
+    {
+        return !mstd::invoke(fn, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    auto operator()(Args&&... args) const & -> decltype(!std::declval<invoke_result_t<std::decay_t<F> const &, Args...>>())
+    {
+        return !mstd::invoke(fn, std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    auto operator()(Args&&... args) && -> decltype(!std::declval<invoke_result_t<std::decay_t<F>, Args...>>())
+    {
+        return !mstd::invoke(std::move(fn), std::forward<Args>(args)...);
+    }
+
+    template<typename... Args>
+    auto operator()(Args&&... args) const && -> decltype(!std::declval<invoke_result_t<std::decay_t<F> const, Args...>>())
+    {
+        return !mstd::invoke(std::move(fn), std::forward<Args>(args)...);
+    }
+};
+}
+
+template <typename F>
+impl::not_fn_t<F> not_fn_t(F&& f)
+{
+    return impl::not_fn_t<F>(std::forward<F>(f));
+}
+#endif
+}
+
+#endif // MSTD_FUNCTIONAL_