[FEA]: Define public version macros for libcudacxx

[jrhemstad]

Is this a duplicate?

• I confirmed there appear to be no duplicate issues for this request and that I agree to the Code of Conduct

Area

libcu++

Is your feature request related to a problem? Please describe.

As a user of CCCL, I want blessed symbols that I can use to query the version of various libraries.

libcudacxx currently has definitions for these in _LIBCUDACXX_API_VERSION, _LIBCUDACXX_API_VERSION_MAJOR/MINOR/PATCH:

cccl/libcudacxx/include/cuda/std/detail/__config

Lines 14 to 23 in bd43e58

	#define _LIBCUDACXX_CUDA_API_VERSION 2002000
	#define _LIBCUDACXX_CUDA_API_VERSION_MAJOR \
	(_LIBCUDACXX_CUDA_API_VERSION / 1000000)
	#define _LIBCUDACXX_CUDA_API_VERSION_MINOR \
	(_LIBCUDACXX_CUDA_API_VERSION / 1000 % 1000)
	#define _LIBCUDACXX_CUDA_API_VERSION_PATCH \
	(_LIBCUDACXX_CUDA_API_VERSION % 1000)

The leading underscore implies that these are internal only symbols and shouldn't be relied on by user code.

Describe the solution you'd like

• Add the following to cuda/std/detail/__config

#define LIBCUDACXX_VERSION _LIBCUDACXX_API_VERSION
#define LIBCUDACXX_VERSION_MAJOR _LIBCUDACXX_API_VERSION_MAJOR
#define LIBCUDACXX_VERSION_MINOR _LIBCUDACXX_API_VERSION_MINOR
#define LIBCUDACXX_VERSION_PATCH _LIBCUDACXX_API_VERSION_PATCH

• Add cuda/std/version and cuda/version that just include cuda/std/detail__config.

Describe alternatives you've considered

No response

Additional context

Eventually we'll want to have a centralized CCCL_VERSION/MAJOR/MINOR/PATCH that libcudacxx/cub/thrust all reference, but this is good for now.

[jrhemstad]

#652