As long as we’re talking Meteor pre v1.7, any lib/ folder will be included in the build automatically.
However, your project is using v1.7, so you will need to explicitly import the files you want to access in the modules you want to access them from (if that makes sense!).
Alternatively, you can enable pre v1.7 behaviour by removing the entire meteor stanza from your package.json. In your case, that’s this entire section:
along with the trailing comma on the preceding line.
Looking at your lib/ files, you are actually using lazy globals (variable names not preceded by let,constorvar`), so you may get away with reverting to pre v1.7 behaviour and doing nothing else.
My recommendation is to bite the bullet and refactor to use proper import/export syntax before the code gets too big to make that a comfortable exercise.