You could also use ExtUtils::MakeMaker couldn't you ? ie, create a directory lib/foo that contains bar.pm, write a standard Makefile.PL, and then in the Makefile.in (used by automake), include a command to run "perl Makefile.PL; make install".
Mind you, I've nothing against you wanting to use Module::Build ... I'm just curious to know if EU::MM is in some way deficient for the purpose of this exercise.
I have not used either module, so I cannot make a technical judgement on the issue. Either way I'll have to include a "perl Makefile.PL; make install" in Makefile.in.