[Process] Dont rely on putenv(), it fails on ZTS PHP

Author: nicolas-grekas

Client.php

@@ -343,6 +343,7 @@ protected function doRequestInProcess($request)
     {
         $deprecationsFile = tempnam(sys_get_temp_dir(), 'deprec');
         putenv('SYMFONY_DEPRECATIONS_SERIALIZE='.$deprecationsFile);
+        $_ENV['SYMFONY_DEPRECATIONS_SERIALIZE'] = $deprecationsFile;
         $process = new PhpProcess($this->getScript($request), null, null);
         $process->run();