[REVIEW] ENH Build with Ninja & Pass ccache variables to conda recipe

[dillon-cullinan]

Changes:

• Enables ninja build system
• Exposes ccache environment variables to the conda build

These changes are required to allow ccache to function correctly and have a high cache hitrate during builds.

[dillon-cullinan]

rerun tests

[harrism]

Question about configurability.

[kkraus14]

We should really make a rapids-build package or something similar that sets these via an activation script instead of passing all of these through the recipe, but we can do that in follow ups I suppose.

[dillon-cullinan]

I'm not sure I understand what you mean. Are you talking about utilizing this: https://conda.io/projects/conda-build/en/latest/resources/activate-scripts.html

[kkraus14]

Yes exactly, we could have a package with an activate script that sets all of these environment variables as expected and then depend on the package in the build section or something similar.

[kkraus14]

@gpucibot merge

[dillon-cullinan]

@gpucibot merge