the script used to cross compile windows legacy clients had two
issues:
    - some dirs were not parametric,
    - it was used for compilation checking on our CI infra.

this patch makes the dirs parametric, and provides another script
that builds the client with bare minimum for checking; e.g. not
building the daemon and contrib to save time.

Change-Id: Idd0d9ebbfcd15b0caf72e09d4ddb3841de9c3d42
Reviewed-by: Anthony Léonard <anthony.leonard@savoirfairelinux.com>