Description:
------------
On Windows, PHP_CONFIG_FILE_PATH is determined during *build* time
(using the environment variable SystemRoot, and falling back to an
empty string if that is not set).

However, when constructing the php_ini_search_path during *run*
time, this constant is ignored, and instead the results of
GetWindowsDirectory() and GetSystemWindowsDirectory() are added to
the INI search path[1].

While in the most typical case either is C:\Windows, both may
actually differ; thus, PHP_CONFIG_FILE_PATH must not be set to any
hard-coded value during *build* time.

[1] <https://github.com/php/php-src/blob/php-7.3.20/main/php_ini.c#L542-L563>


Test script:
---------------
<?php
var_dump(getenv("SystemRoot"), PHP_CONFIG_FILE_PATH);
?>


Expected result:
----------------
string(10) "D:\WINDOWS"
string(10) "D:\WINDOWS"



Actual result:
--------------
string(10) "D:\WINDOWS"
string(10) "C:\WINDOWS"