Both XSI and upstream Gnulib versions expects to find poll.h at
the root of some include path, not inside the sys-folder.
This helps us when upgrading Gnulib.
Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>