Comment 4 for bug 1295723

They just (in debian, it's already in trusy/cloud archive) added support to do this:

libv8-3.14 (3.14.5.8-4) unstable; urgency=low

  [ Jérémy Lal ]
  * Patch: 0013_gcc_48_compat, closes: bug#701312.
  * Allow Build-Dependency on latest libv8 branch version or on a
    specific branch: libv8-<API>-dev or libv8-dev.
    Ensure switching from one dev package to another works properly.
    Add a specific case for libv8-3.14 (<=3.14.5.8-3).

mongodb in trusty can be made to depend on that specific -<API>-

Can we reopen this? This fix should work fine in trusty too.