mail function does not detect Windows

Hi @SuneK
I have added a patch for this , please review.
Thanks

Thanks for working on this. The same condition is used in mail.inc:

define('MAIL_LINE_ENDINGS', isset($_SERVER['WINDIR']) || (isset($_SERVER['SERVER_SOFTWARE']) && strpos($_SERVER['SERVER_SOFTWARE'], 'Win32') !== FALSE) ? "\r\n" : "\n");

Which is related to this: 🐛 [D7] PhpMail : broken mail headers in PHP 8.0+ because of LF characters Needs work . If we are going to change, we need to synchronize both issues, or change it here for both places.

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I think the condition is not correct:

+++ b/modules/system/system.mail.inc
-    if (!isset($_SERVER['WINDIR']) && (!isset($_SERVER['SERVER_SOFTWARE']) || strpos($_SERVER['SERVER_SOFTWARE'], 'Win32') === FALSE)) {
+    if (stripos(PHP_OS, 'WIN') === FALSE) {

Because it will return FALSE even for Darwin, CYGWIN_NT-5.1, ... See the list of possible values: https://stackoverflow.com/questions/738823/possible-values-for-php-os

We should probably check something like this (it is already used in core):

substr(PHP_OS, 0, 3) != 'WIN'

or

!(stripos(PHP_OS, 'WIN') === 0);

Raised an MR for the issue and addressed the feedback shared in #4. Please review.

Thank you.