[clang] [llvm] [Clang] Add env var for nvptx-arch/amdgpu-arch timeout (PR #102521)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> > Possibly worth increasing it to a minute then,
> 
> Should we also land the env var? If so, I'll just extend this patch.
> 
> Either way, any objection to moving `[Default]SecondsToWait` into executeToolChainProgram so we're maintaining it in just one place?
> 
> > this is basically just a last ditch effort to prevent builds from hanging forever. I've had it happen personally where either the CUDA or AMDGPU drivers were stuck, and when I tried to rebuild `libc` `ninja` just hung indefinitely and it took me awhile to figure out why.
> 
> I'm not sure how often the situation you describe occurs in practice. Hopefully a 60-second pause on a simple compilation doesn't prompt the same confusion and a premature Ctrl+C.

You can just do both in the same patch, I don't think it's too important.

https://github.com/llvm/llvm-project/pull/102521