by default do not pass a rust source

[lu-zero]

This way the racer default can be used.

It would make it work out of box on rustup setups.

[qzed]

This would definitely be an improvement. A temporary workaround to automatically detect the rustup source component would be to add something like this to the init script:

do setRustSrcPath = () ->
    exec = require('child_process').exec

    exec 'rustc --print sysroot', (error, stdout, stderr) ->
        if error
            atom.notifications.addFatalError 'failed to determine rust source path: ' + stderr
        path = stdout.trim() + '/lib/rustlib/src/rust/src'
        atom.config.set 'racer.rustSrcPath', path

I'm not sure if this is a 100% correct (and good idea due to the asynchronous execution) though.

[lu-zero]

#79 this is the current kludge that works well enough to me.