[0.5.0-RC2] Better explain multithreading in compilation message

[spamegg1]

Currently it says:

Linking (multithreadingEnabled=true, disable if not used) (2289 ms)

I thought it was asking me to disable it, so I was searching for a nativeConfig option to disable it.

According to this PR it is enabled by default, automatically disables itself if not used.

Not sure what the correct message should be. Something like:

Linking (multithreadingEnabled=true by default, will be disabled automatically if not used) (2289 ms)

or maybe

Linking (multithreadingEnabled=true) (2289 ms)

...

Linking (multithreadingEnabled=false since it was not detected to be used) (2289 ms)

or maybe just don't mention it at all, since it's disabled when unused, enabled when used.

[spamegg1]

Currently on 0.5.0 it says:

[info] Multithreading was not explicitly enabled - initial class loading has not detected any usage of system threads. Multithreading support will be disabled to improve performance.

Looks good! 👍