AC_DEFUN([ARABICA_HAS_STD_WSTRING],
[
  AC_MSG_CHECKING([for std::wstring support])
  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <string>]],
                                     [[std::wstring test;]])],
                    [AS_VAR_SET(wchar_t_available, yes)],
                    [AS_VAR_SET(wchar_t_available, no)])
  AC_MSG_RESULT($wchar_t_available)
  if test $wchar_t_available = no; then
    AC_DEFINE(ARABICA_NO_WCHAR_T, ,[disables wchar_t])
  fi
])