solution 1:
   % perl Build1.PL
   % perl Build2.PL ...
  
   solution 2:
   % cd staging/one-dist
   % ln -s ourstuff/lib staging/one-dist
   % perl Build.PL ...

   solution 3: supplement Module::Build with make or ant
   solution 4: use Module::Build as an API and write
     some sort of software around it