Return false in isTtySupported() when open_basedir restrictions prevent access to /dev/tty.

If open_basedir restrictions are in effect, checking if the file /dev/tty is writable will prevent setting tty mode on the process, and avoid failing to create a Process.

Author: mjauvin

Process.php

@@ -1211,7 +1211,7 @@ public static function isTtySupported(): bool
     {
         static $isTtySupported;
 
-        return $isTtySupported ??= ('/' === \DIRECTORY_SEPARATOR && stream_isatty(\STDOUT));
+        return $isTtySupported ??= ('/' === \DIRECTORY_SEPARATOR && stream_isatty(\STDOUT) && @is_writable('/dev/tty'));
     }
 
     /**