wafsamba: Fail with error message if perl doesn't provide valid dirs.

wafsamba: Fail with error message if perl doesn't provide valid dirs.

We try harder to get valid directories, we now fallback like this:

vendorarch => sitearch => archlib
and
vendorlib => sitelib => privlib

The new options are --with-perl-arch-install-dir and
--with-perl-lib-install-dir.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=10472

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
(cherry picked from commit 2637890ef42a238093f0f3cbdda0d621d5f9b2e2)