Let the D compiler print the dependencies.

[Frank Benoit (keinfarbton)]

> (I also think it should print filnames
> and not moduenames, or have two switches)

If the file is actually missing, the compiler perhaps does not know the
filename. It can be in a missing search path and it can be a .d or .di
file. So printing the module name will always work.

The build tool can than search in in the project folders or can start a
download of the missing sources, or something like that... then start a
new compile run.