Okay, all
I have go a big bunch of advice, so I understand things a little bit better now, I think.
I put in all the parameters given to me here into the project settings, but unfortunately it did not solve my initial question:
Line 9 in ./wx_pch.h in my barebones wxWidgets template project,
#include <wx/wxprec.h>
gives an error during the generation of the precompiled headers that the file is not found.
So it still don't know where wx is.
Again, the complete path to wxprec.h is:
/opt/local/include/wx-2.6/wx/wxprec.h
What more can I do?