Broken compatability with PHP 8.1+

[blizzard4591]

Dear maintainers,

the file ScriptEngine/php_sapi.cpp says it is compatible with PHP 8.1 and changes to that end seem to have been made, but when compiling, this happens:

ScriptEngine/php_sapi.cpp: In function ‘zend_result hg_stream_open(const char*, zend_file_handle*)’:
ScriptEngine/php_sapi.cpp:468:26: error: cannot convert ‘const char*’ to ‘zend_string*’ {aka ‘_zend_string*’} in assignment
  468 |       handle->filename = filename;
      |                          ^~~~~~~~
      |                          |
      |                          const char*
ScriptEngine/php_sapi.cpp:524:28: error: cannot convert ‘const char*’ to ‘zend_string*’ {aka ‘_zend_string*’} in assignment
  524 |         handle->filename = filename;
      |                            ^~~~~~~~
      |                            |
      |                            const char*
ScriptEngine/php_sapi.cpp:546:26: error: cannot convert ‘const char*’ to ‘zend_string*’ {aka ‘_zend_string*’} in argument passing
  546 |     auto fp = zend_fopen(filename, &opened_path);
      |                          ^~~~~~~~
      |                          |
      |                          const char*
ScriptEngine/php_sapi.cpp: In function ‘int php_homegear_startup(sapi_module_struct*)’:
ScriptEngine/php_sapi.cpp:2694:31: error: invalid conversion from ‘zend_result (*)(const char*, zend_file_handle*)’ {aka ‘ZEND_RESULT_CODE (*)(const char*, _zend_file_handle*)’} to ‘zend_result (*)(zend_file_handle*)’ {aka ‘ZEND_RESULT_CODE (*)(_zend_file_handle*)’} [-fpermissive]
 2694 |   zend_stream_open_function = hg_stream_open;
      |                               ^~~~~~~~~~~~~~
      |                               |
      |                               zend_result (*)(const char*, zend_file_handle*) {aka ZEND_RESULT_CODE (*)(const char*, _zend_file_handle*)}

Looking at the Zend release notes at https://raw.githubusercontent.com/php/php-src/PHP-8.1/UPGRADING.INTERNALS, we can see:
zend_file_handle.filename now is zend_string*

Am I doing something wrong? I used PHP 8.1.24 built from source using the instructions at https://doc.homegear.eu/homegear/installation.html#compiling-from-source.

Sadly, I have no idea how to fix this, i.e. how to get a zend_string from a std::string.