dos2unix: add target support

Allow the `dos2unix` utility to be built and installed on the target
system.

[baruch: properly handle target gettext]
Signed-off-by: James Knight <james.knight@rockwellcollins.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Tested-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>