[php-src] Issue #12303: Headers sent in CLI SAPI

Issue: https://github.com/php/php-src/issues/12303 Author: joanhey ### Description It's an historical bug !! The following code: ```php <?php echo 'Hello'; ini_set('session.name', 'SID'); ``` Resulted in this output: ``` Hello Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in /in/HIReN on line 4 ``` But I expected this output instead: ``` Hello ``` For a lot of time the developers by pass this problem with tricks: https://3v4l.org/rJdZo ```php <?php fwrite(STDOUT, 'Hello'); ini_set('session.name', 'SID'); fwrite(STDOUT, "\n" . ini_get('session.name')); ``` And also setting an error handler, because when output an error happen the same: https://3v4l.org/3lEcj ```php <?php set_error_handler(function ($code, $msg, $file, $line) { fwrite(\STDERR, "$msg in file $file on line $line\n"); }); $foo = $bar; ini_set('session.name', 'SID'); echo ini_get('session.name'), PHP_EOL; ``` The first difference of the CLI SAPI is that no headers are written to the output !! https://www.php.net/manual/en/features.commandline.differences.php Still show the error: headers have already been sent in, when the default behavior is to send the output to terminal, without the need for extra tricks. The php-src code in the CLI SAPI: https://github.com/php/php-src/blob/master/sapi/cli/php_cli.c#L395-L400 **BC**: Nothing In fact we can simplify cli apps by removing the tricks to by pass this problem. ### PHP Version All versions ### Operating System All