glibc/wctype/Versions

libc {
  GLIBC_2.0 {
    # functions used in inline functions or macros
    __iswctype;

    # i*
    iswalnum; iswalpha; iswcntrl; iswctype; iswdigit; iswgraph; iswlower;
    iswprint; iswpunct; iswspace; iswupper; iswxdigit;

    # t*
    towctrans; towlower; towupper;

    # w*
    wctrans; wctype; wcwidth;
  }
  GLIBC_2.1 {
    # i*
    iswblank;
  }
}