Cannot get override_function to work on PHP7

[ericol]

I compiled the extension just fine on PHP7:

php -v
PHP 7.0.10-1~dotdeb+8.1 (cli) ( NTS )
Copyright (c) 1997-2016 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies
    with Better Function Replacer (BFR) v0.1, Copyright (C) 2015, by Lukas Rist

I'm using this code to test:

<?php
$ren=rename_function('strlen', 'old_strlen');
$ovr=override_function('strlen', '$string', 'return override_lenstr($string);');
function override_strlen($string) {
        return 'THIS TEXT IS ADDED '.old_strlen($string);
}
echo "Results of rename and replace: |{$ren}|{$ovr}|\n";
$var='some string to be measured';
echo "The length of '{$var}' is (override) ".strlen($var)."\n";
echo "The length of '{$var}' is (rename) ".old_strlen($var)."\n";

This is the result:

Results of rename and replace: |1||
The length of 'some string to be measured' is (override) 26
The length of 'some string to be measured' is (rename) 26

As a side note, if I remove line 3 of above (the override_function line) strlen is still available.
Also, override_function never returns true.

Regards.