Because ICS is entirely supported by volunteers, and none of us understand C++. It would be far easier to cease support for C++.
I've asked for assistance in producing C++ packages in the past, and one user kindly supplied some mostly working stuff, for 10.2 which I modified for 10.3, so renaming errors are mine. But when I can not build the packages and no-one else helps, errors are inevitable.
So will some-one please email me a complete working set of 10.3 C++ package files, with whatevery changes are needed for the readme, and they will be placed in the distribution. I'm not going to work from a list of instructions I can not test.
Angus