sys/new_delete: add malloc/free based new/delete implementation

cpu/avr8_common/Kconfig

@@ -14,6 +14,8 @@ config CPU_ARCH_AVR8
     select MODULE_MALLOC_THREAD_SAFE if TEST_KCONFIG
     # static C++ constructors need guards for thread safe initialization
     select MODULE_CXX_CTOR_GUARDS if MODULE_CPP
+    # new and delete operators needed
+    select MODULE_CPP_NEW_DELETE if MODULE_CPP
 
 ## Common CPU symbols
 config CPU_ARCH

cpu/avr8_common/Makefile.dep

@@ -18,3 +18,8 @@ endif
 ifneq (,$(filter cpp,$(FEATURES_USED)))
   USEMODULE += cxx_ctor_guards
 endif
+
+# new and delete operators needed
+ifneq (,$(filter cpp,$(FEATURES_USED)))
+  USEMODULE += cpp_new_delete
+endif

sys/Kconfig

@@ -19,6 +19,7 @@ rsource "checksum/Kconfig"
 rsource "color/Kconfig"
 rsource "crypto/Kconfig"
 rsource "congure/Kconfig"
+rsource "cpp_new_delete/Kconfig"
 rsource "cxx_ctor_guards/Kconfig"
 rsource "div/Kconfig"
 rsource "embunit/Kconfig"

sys/cpp_new_delete/Kconfig

@@ -0,0 +1,17 @@
+# Copyright (C) 2021 Gunar Schorcht
+#
+# This file is subject to the terms and conditions of the GNU Lesser
+# General Public License v2.1. See the file LICENSE in the top level
+# directory for more details.
+#
+
+config MODULE_CPP_NEW_DELETE
+    bool
+    depends on TEST_KCONFIG
+    depends on MODULE_CPP
+    help
+        On some platforms libstdc++ is not used or not available, like on
+        the AVR. Such platforms can use this module to implement the C++
+        new and delete operators using malloc and free respectively. However,
+        to be thread-safe, a thread-safe implementation of malloc and free
+        must be present.

sys/cpp_new_delete/Makefile

@@ -0,0 +1,3 @@
+include $(RIOTBASE)/Makefile.base
+
+CXXFLAGS += -std=c++11

sys/cpp_new_delete/doc.txt

@@ -0,0 +1,22 @@
+/**
+@defgroup   sys_cpp_new_delete  C++ new and delete operator module
+@ingroup    sys
+@brief      This module provides the `new` and `delete` operators for platforms
+            that do not use `libstdc++`.
+@warning    This module is automatically selected, if needed. Never add it
+            manually.
+
+# Background
+
+On some platforms `libstdc++` is not used or not available, like on the AVR.
+Such platforms can use this module to implement the C++ `new` and `delete`
+operators using `malloc` and `free` respectively. However, to be thread-safe,
+a thread-safe implementation of `malloc` and `free` must be present.
+
+# Usage
+
+This module is intended to be use by platforms that not providing the required
+operators. Hence, application developers and users should never select this
+module by hand.
+
+ */

sys/cpp_new_delete/new_delete.cpp

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2014 Arduino.  All right reserved.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <stdlib.h>
+
+void *operator new(size_t size) {
+    return malloc(size);
+}
+
+void *operator new[](size_t size) {
+    return malloc(size);
+}
+
+void *operator new(size_t size, void *ptr) noexcept {
+    (void)size;
+    return ptr;
+}
+
+void operator delete(void *ptr) {
+    free(ptr);
+}
+
+void operator delete[](void *ptr) {
+    free(ptr);
+}