[Issue 13517] Only touch .di generated file if changed

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13517

--- Comment #8 from Andrei Alexandrescu <andrei at erdani.com> ---
(In reply to Walter Bright from comment #6)
> The generated object file isn't compared against the existing one, why
> should other generated files? It seems strange to me to make the .di
> generation special in this way.

Thanks for asking. The difference here is that only the linked binary depends
on the .o file, whereas a lot more build artifacts depend on the .di file.

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