Translate C++ to C for Objective C

I have translated RBC_CPP.cpp to RBC_C.c in plain C (which already was in 99%).
This way it's more clear. It can be compiled to C, C++ and Objective C.

My results are what's expected on the overall, but the lack of consistency between clang and GCC is a little disconcerting. Looks like there's some optimization voodoo over there. Or maybe it's my machine (MacBookPro 2.4GHz Intel Core 2 Duo)?

Language     | clang    |  GCC    
-------------|----------|---------
Objective-C  | 1.91848  |  2.74969
C            | 2.75318  |  1.92625
C++          | 2.76323  |  2.78382