since linker can't find basic_string::~basic_string() oddly:
arm-none-eabi-ld: /home/xiaoxiang/backup/os/nuttx/nuttx/staging/libxx.a(libcxx/src/locale.o): in function `__tcf_0':
/home/xiaoxiang/backup/os/nuttx/nuttx/libs/libxx/libcxx/src/locale.cpp:4941: undefined reference to `std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::~basic_string()'
another fix is removing the follow code from _LIBCPP_STRING_V1_EXTERN_TEMPLATE_LIST and _LIBCPP_STRING_UNSTABLE_EXTERN_TEMPLATE_LIST:
_Func(_LIBCPP_FUNC_VIS basic_string<_CharType>::~basic_string()) \
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
