diff --git a/libcxx/include/cstdlib b/libcxx/include/cstdlib
--- a/libcxx/include/cstdlib
+++ b/libcxx/include/cstdlib
@@ -136,10 +136,12 @@
 using ::ldiv _LIBCPP_USING_IF_EXISTS;
 using ::lldiv _LIBCPP_USING_IF_EXISTS;
 using ::mblen _LIBCPP_USING_IF_EXISTS;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 using ::mbtowc _LIBCPP_USING_IF_EXISTS;
 using ::wctomb _LIBCPP_USING_IF_EXISTS;
 using ::mbstowcs _LIBCPP_USING_IF_EXISTS;
 using ::wcstombs _LIBCPP_USING_IF_EXISTS;
+#endif
 #if !defined(_LIBCPP_CXX03_LANG)
 using ::at_quick_exit _LIBCPP_USING_IF_EXISTS;
 using ::quick_exit _LIBCPP_USING_IF_EXISTS;
diff --git a/libcxx/include/iosfwd b/libcxx/include/iosfwd
--- a/libcxx/include/iosfwd
+++ b/libcxx/include/iosfwd
@@ -121,7 +121,9 @@
 
 template <class _State>             class _LIBCPP_TEMPLATE_VIS fpos;
 typedef fpos<mbstate_t>    streampos;
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
 typedef fpos<mbstate_t>    wstreampos;
+#endif
 #ifndef _LIBCPP_HAS_NO_CHAR8_T
 typedef fpos<mbstate_t>    u8streampos;
 #endif