don't generate any dependencies on modules therein.
-Xdirs same as --exclude-directory
--include-prelude
- Regard prelude library as unstable, i.e., generate dependencies
+ Regard prelude libraries as unstable, i.e., generate dependencies
on prelude modules. This option is normally only used by the
various system libraries. If a -syslib option is used, dependencies
will also be generated on the library's interfaces.