s/Haiku License/MIT License/g.

They are the same thing.

posix_spawn: add posix_spawn_file_actions_add[f]chdir_np.

see http://austingroupbugs.net/view.php?id=1208
and https://sourceware.org/bugzilla/show_bug.cgi?id=17405

* also free paths in posix_spawn_file_actions_destroy().

Change-Id: I8bed848154025bd5a25322bdc4c25aa417f86ec6
Reviewed-on: https://review.haiku-os.org/c/1010
Reviewed-by: Rene Gollent <rene@gollent.com>