Hi petermc,
I'm in the same situation: Xcode got upgraded to v7, applied fix, and everything worked as expected again, but C++ header files now use the .hpp extension.
Using .hpp instead of .h doesn't make any difference in general terms, and OF handles them properly. It's a matter of naming conventions: officially, C headers should be some_class.h while C++ headers should be some_class.hpp. But both are essentially the same when using C++.
Don't know how to go back to .h in Xcode 7 though.
