I am the sole author of a piece of C++ software which so far I have kept under the GPL license. For uninteresting reasons, I am considering a switch to a MIT/BSD style license. As far as I have understood, this would prevent, in the future, to use any kind of GPL component (library, header, plugin, etc.) in my MIT/BSD licensed software.
Would it make any sense then to dual-license the software under both BSD and GPL? I would add a switch in the build system to enable/disable the component of my software that relies on GPLed 3rd party code and document that, if the user builds the software with that option enabled, then she must choose the GPL license. Otherwise, she is able to choose whichever license she likes.
Would that be a suitable course of action? How should I word this in a README file?