Unluckily, writing a program bigger than HelloWorld that compiles with both wxWidgets 2.6 and 2.8 and which still remains intellegible and maintainable is a daunting task, if not next to impossible. Debugging is a nightmare, maintenance a nuisance.
The patches you refer to are not likely to be applied in their present form, as they add yet more preprocessor branches and macros as there are already and make our code yet more unreadable and unmaintainable.
During the last 1-2 weeks, we've undergone a lot of pain in order to remove most of the already existing code abuse.
Eventually all wxWidgets 2.8 incompatibilities will be solved, but it is not entirely trivial without poisoning the code again.
I understand your concern about just being able to compile. But we, too, have to be able to still read our code and understand what it does.