[clj] Add clj to modules in lfe.app.src

[yurrriq]

Without it, I can't use clj functions in a release. Could've sworn I did this, but "computer says no."

[yurrriq]

Note: for whatever reason lfe doesn't seem to play nice with rebar3 in _checkouts/...

[yurrriq]

There seems to be another issue at play here... when running a release:

1> cl:module_info().
** exception error: undefined function cl:module_info/0
2> clj:module_info().
** exception error: undefined function clj:module_info/0
3> lfe_doc:module_info().
[{module,lfe_doc},
 %% ...
]

[yurrriq]

Even more curious, code:which(clj) returns the path to clj.beam...

[yurrriq]

The following makes everything ok again:

4> code:ensure_modules_loaded([cl,clj]).
ok

[yurrriq]

As a (possibly temporary) workaround, I've added

(let (('ok (code:ensure_modules_loaded '[clj]))))

to start/2 in my apps that depend on lfe at runtime.

Regardless we should add clj to modules in lfe.app.src.

[yurrriq]

Maybe we should make lfe.erl implement the application behaviour and call code:ensure_modules_loaded([cl,clj]) there...