the infrastructure put in place to manage cuda buffers is actually
a lot more generic than just for cuda buffers. Specifically, we ca
reuse much of the code to implement the external32 data representation.
This commit converts the code from common_ompio_cuda* to
common_ompio_buffer*. There are just very few places where we actually need to keep the OPAL_CUDA_SUPPORT ifdef in place.
Signed-off-by: Edgar Gabriel <egabriel@central.uh.edu>