This commit reverts c34f13a02d

In stripped plugin builds, the repostCurrentNSEvent function was still
public. There doesn't seem to be a good reason for this, as no host
should need to call the function.

It looks like the shared code component of a Projucer-generated plugin
project was briefly built as a framework that was shared by the
different plugin wrappers. In this scenario, the framework would need to
make repostCurrentNSEvent public so that the wrappers could locate the
function. However, now that the shared code target is built as a static
library, standard external linkage should be sufficient for the symbol
to be located from the wrapper's TUs.