Summary:
This simplifies the jbuild files: no need to list these files explicitly
anymore, nor to exclude them explicitly from the main `InferModules` library
(due to their different compilation flags).
Isolate common parts into jbuild.common do `cat`-based code inclusion into
jbuild files to factorize code.
Reviewed By: jberdine
Differential Revision: D5678328
fbshipit-source-id: 6d7d925