Adding ccache-like output caching to dmd

[John Colvin]

On Tuesday, 29 December 2020 at 19:57:21 UTC, Per Nordlöw wrote:
> On Tuesday, 29 December 2020 at 16:43:33 UTC, John Colvin wrote:
>> Or something like that, you get the idea... It's not 
>> intractable, it's just a bit fiddly.
>
> Superb answer.
>
> Does this design match https://github.com/dlang/dub/pull/2044

Not really, although maybe it should?

If I understand correctly (I haven't reviewed the 
implementation), that PR is using dub's normal rebuild rules 
w.r.t. changed files and is just swapping out access times for 
content hashes. Maybe I'm mistaken, but I don't think dub pays 
any attention to changes in files that aren't source files.