add hello_world example for cpp

apps/c/cpp_helloworld/axbuild.mk

@@ -0,0 +1,20 @@
+ARCH ?= x86_64
+C_COMPILER := $(shell which $(CC))
+CXX_COMPILER := $(shell which $(CC))
+AR := $(shell which $(AR))
+RANLIB := $(shell which $(RANLIB))
+CROSS_COMPILE_PATH := $(shell dirname $(C_COMPILER))/..
+
+app-objs := main.o
+
+$(APP)/$(app-objs): $(APP)/axbuild.mk
+	$(CXX_COMPILER) -c -o $(app-objs) $(APP)/main.cpp
+	$(LD) -o $(app-objs) -nostdlib -static -no-pie -r -e main \
+		$(app-objs) \
+		$(CROSS_COMPILE_PATH)/*-linux-musl/lib/libstdc++.a \
+		$(CROSS_COMPILE_PATH)/lib/gcc/*-linux-musl/*/libgcc_eh.a
+
+clean_c::
+	rm -rf $(APP)/$(app-objs) 
+
+.PHONY: $(APP)/$(app-objs) clean_c

apps/c/cpp_helloworld/features.txt

@@ -0,0 +1,6 @@
+alloc
+paging
+irq
+multitask
+fs
+random-hw

apps/c/cpp_helloworld/main.cpp

@@ -0,0 +1,12 @@
+#include <iostream>
+
+using namespace std;
+
+// This is a dummy function to avoid linker errors as this example should be a static executable.
+void* __dso_handle = NULL;
+
+int main(int argc, char* argv[]) {
+	cout << "Hello, wolrd!" << endl;
+	return 0;
+}
+