Not that it directly answers your question but Easysoft do have an ARM build of unixODBC and the SQL Server driver. If you msg me I will provide you with contact details.

From Perl, did you look at DBD::Proxy which I believe is pure Perl and if cannot get a pure Perl version of DBI on ARM try posting to the dbi-users list (see dbi.perl.org and the support link) where I'm sure someone could help.