In that case you can use DESTDIR and TARGET. But ensure you use OUT_PWD so you ensure that your get the proper build folder to store the build artefact.
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@Wieland Thanks for the reference - that has worked for me.
Also, thanks for the Qbs information - i hadn't seen this before but will look into it
@SGaist - thanks for the info
I had previously tried something similar but I think it may have been the escaping of quotes which caught me out.
However I'd recommend to rather have a comms.pri file that you include in your application .pro file that will do that.