Description:
------------
Calling `getenv()` without an argument does not reflect change made with `putenv`, but calling `getenv()` on a concrete variable *does*.

The test script below produces the expected output on a Linux machine, but on my Windows machine the array difference is "array(0) { }".

I'm using the out-of-the box configuration of php.ini-development.

These are the first lines of `php -i`

System => Windows NT MYPC 10.0 build 18363 (Windows 10) AMD64
Build Date => Jan 21 2020 17:46:05
Compiler => Visual C++ 2017
Architecture => x64
Configure Command => cscript /nologo configure.js  "--enable-snapshot-build" "--enable-debug-pack" "--with-pdo-oci=c:\php-snap-build\deps_aux\oracle\x64\instantclient_12_1\sdk,shared" "--with-oci8-12c=c:\php-snap-build\deps_aux\oracle\x64\instantclient_12_1\sdk,shared" "--enable-object-out-dir=../obj/" "--enable-com-dotnet=shared" "--without-analyzer" "--with-pgo"
Server API => Command Line Interface
Virtual Directory Support => enabled
Configuration File (php.ini) Path => C:\WINDOWS
Loaded Configuration File => C:\xampp\php\php.ini
Scan this dir for additional .ini files => (none)
Additional .ini files parsed => (none)
PHP API => 20190902
PHP Extension => 20190902
Zend Extension => 320190902
Zend Extension Build => API320190902,TS,VC15
PHP Extension Build => API20190902,TS,VC15
Debug Build => no
Thread Safety => enabled
Thread API => Windows Threads
Zend Signal Handling => disabled
Zend Memory Manager => enabled
Zend Multibyte Support => disabled
IPv6 Support => enabled
DTrace Support => disabled

Test script:
---------------
<?php

$old = getenv();
var_dump(getenv("FOO", true));    // expected: bool(false)

putenv("FOO=BAR");

$new = getenv();
var_dump(array_diff($new, $old)); // expected: array(1){["FOO"]=>string(3) "BAR"}
var_dump(getenv("FOO", true));    // expected: string(3) "BAR"

?>

Expected result:
----------------
bool(false)
array(1) {
  ["FOO"]=>
  string(3) "BAR"
}
string(3) "BAR"

Actual result:
--------------
bool(false)
array(0) {
}
string(3) "BAR"