DCompute: First kernels run successfully

[kerdemdemir via Digitalmars-d-announce]

Hi Wilson,

Since I believe GPU-CPU hybrid programming is the future I 
believe you are doing a great job for your and D lang's future.

> To successfully run the dcompute CUDA test you will need a very 
> recent LDC (less than two days) with the NVPTX backend* enabled 
> along with a CUDA environment and an Nvidia GPU.
>
> *Or wait for LDC 1.4 release real soon(™).

Can you please describe a bit about for starters like me how to 
build recent LDC.

Is this "NVPTX backend" a cmake option?
And what should I do for making my "CUDA environment" ready? 
Which packages should I install?

Sorry if my questions are so dummy I hope I will be able to add 
an example.

Regards
Erdem