cpp: new: Add no-throwing implementation of new operator

C++ subsystem defines exception throwing operator new.
Though the implementation never throws an exception.

If used by an application it should verify if requested
memory was allocated. This is against C++ standard.
If an application does not support exceptions or does not
want to call throwing new operator, it should use a
specialization of a new operator that makes sure it
never throws bad_alloc exception. The cpp subsystem
does not provide this specialization.

The commit adds missing operator new specializations.

Signed-off-by: Piotr Pryga <piotr.pryga@nordicsemi.no>

subsys/cpp/cpp_new.cpp

@@ -22,6 +22,16 @@ void* operator new[](size_t size)
 	return malloc(size);
 }
 
+void* operator new(std::size_t size, const std::nothrow_t& tag) NOEXCEPT
+{
+	return malloc(size);
+}
+
+void* operator new[](std::size_t size, const std::nothrow_t& tag) NOEXCEPT
+{
+	return malloc(size);
+}
+
 void operator delete(void* ptr) NOEXCEPT
 {
 	free(ptr);

subsys/cpp/include/new

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2022 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ *
+ * @brief Stub header allowing compilation of `#include <new>`
+ */
+
+#ifndef ZEPHYR_SUBSYS_CPP_INCLUDE_NEW_
+#define ZEPHYR_SUBSYS_CPP_INCLUDE_NEW_
+
+#include <cstddef>
+
+namespace std {
+#if __cplusplus < 201103L
+	struct nothrow_t {};
+#else
+	struct nothrow_t {
+		explicit nothrow_t() = default;
+	};
+#endif /* __cplusplus */
+	extern const std::nothrow_t nothrow;
+}
+
+#endif /* ZEPHYR_SUBSYS_CPP_INCLUDE_NEW_ */