Description:
------------
The proto and description of php_strip_whitespace() indicate it should return a stripped string. It does not do this and instead outputs the stripped code to stdout.

It looks like the function IS intended to return the stripped string as the code uses output buffering, but the problem lies in php_strip().

Unlike highlight_file() which uses zend_printf()'s and ZEND_PUTC()'s and what-have-you so output buffering works and the result is captured, php_strip() is hardcoded to output to stdout which means the output buffering intended for php_strip_whitespace() doesn't work and an empty string is returned for this function.

It also means, for Apache, since stdout goes nowhere (I think?), nothing is even outputted to the browser.

Fixing this would also close #28280. (same function, different issue)

Reproduce code:
---------------
<?php
/* ... */
var_dump(php_strip_whitespace($_SERVER['SCRIPT_FILENAME']));
?>

Expected result:
----------------
string(63) "<?php
var_dump(php_strip_whitespace($_SERVER['SCRIPT_FILENAME'])); ?>"

Actual result:
--------------
CLI:

<?php
var_dump(php_strip_whitespace($_SERVER['SCRIPT_FILENAME'])); ?>
string(0) ""

Apache:
string(0) ""