Steps to reproduce the issue

Install Joomla 4 and open a view having a TinyMCE editor

Expected result

No errors, all works fine

Actual result

error 0: Undefined constant "GLOB_BRACE"

Additional comments

The line 477 of the file tinymce.php uses the 'GLOB_BRACE' flag:
foreach (glob(JPATH_ROOT . $template_path . '/*.{html,txt}', GLOB_BRACE) as $filepath)

but: The GLOB_BRACE flag is not available on some non GNU systems, like Solaris or Alpine Linux.
see: https://www.php.net/manual/en/function.glob.php

That one should be removed