I'm creating a meteor package for a JS library that contains a number of optional plugins in the main repository. I would like to provide the option for the user to select which library extensions to use, without always including them unnecessarily.
Is this possible with the current build system? If so, where do I begin?
This is not currently supported. In a sense, each package is the "option" you enable through the package system itself. Your current best bet is to just publish packages for each piece and maybe add packages for common build combinations.
Twitter Bootstrap currently does something similar like so:
twbs:bootstrap // normal bootstrap
twbs:bootstrap-noglyph // bootstrap sans glpyhs
Also relevant, some of the (many) pre-packaged stylus packages out there:
stolinski:stylus-multi
cryptoquick:stylus-multi
mquandalle:stylus
I look forward to this answer going stale.