Function Perl_bytes_cmp_utf8 

pub unsafe fn Perl_bytes_cmp_utf8(
    my_perl: *mut PerlInterpreter,
    b: *const U8,
    blen: STRLEN,
    u: *const U8,
    ulen: STRLEN,
) -> c_int

thx shim for crate::Perl_bytes_cmp_utf8.