private fun compile_extern_callback(v: AbstractCompilerVisitor, ccu: CCompilationUnit, compile_implementation_too: Bool)
	do
		var mproperty = from.mproperty
		assert mproperty isa MMethod
		var mclass_type = from.mclassdef.mclass.mclass_type

		# In nitni files, declare internal function as extern
		var internal_csignature = mproperty.build_csignature(mclass_type, v.compiler.mainmodule, "___super", long_signature, internal_call_context)
		ccu.header_decl.add("extern {internal_csignature};\n")

		# In nitni files, #define friendly as extern
		var friendly_cname = mproperty.build_cname(mclass_type, v.compiler.mainmodule, "___super", short_signature)
		var internal_cname = mproperty.build_cname(mclass_type, v.compiler.mainmodule, "___super", long_signature)
		ccu.header_decl.add("#define {friendly_cname} {internal_cname}\n")

		if not compile_implementation_too then return

		# Internally, implement internal function
		var nitni_visitor = v.compiler.new_visitor
		nitni_visitor.frame = v.frame
		var msignature = mproperty.lookup_first_definition(v.compiler.mainmodule, mclass_type).msignature

		var csignature_blind = mproperty.build_csignature(mclass_type, v.compiler.mainmodule, "___super", long_signature, internal_call_context)

		nitni_visitor.add_decl("/* nitni callback to super for {mproperty.full_name} */")
		nitni_visitor.add_decl("{csignature_blind} \{")

		var vars = new Array[RuntimeVariable]

		var recv_var = nitni_visitor.var_from_c("self", mclass_type)
		recv_var = nitni_visitor.box_extern(recv_var, mclass_type)
		vars.add(recv_var)

		for p in msignature.mparameters do
			var arg_mtype = v.anchor(p.mtype)
			var arg = nitni_visitor.var_from_c(p.name, arg_mtype)
			arg = nitni_visitor.box_extern(arg, arg_mtype)
			vars.add(arg)
		end

		var ret_var = nitni_visitor.supercall(from.as(MMethodDef), mclass_type, vars)

		var return_mtype = msignature.return_mtype
		if return_mtype != null then
			assert ret_var != null
			return_mtype = v.anchor(return_mtype)
			ret_var = nitni_visitor.autobox(ret_var, return_mtype)
			ret_var = nitni_visitor.unbox_extern(ret_var, return_mtype)
			nitni_visitor.ret_to_c(ret_var, return_mtype)
		end
		nitni_visitor.add("\}")
	end