[m-rev.] for review: Delete references to Erlang backend in makefiles.

[Julien Fischer]

On Mon, 26 Oct 2020, Peter Wang wrote:

> Mmake.workspace:
> Mmakefile:
> */Mmakefile:
> tests/*/Mmakefile:
> tests/valid/Mmake.valid.common:
> trace/Mmakefile:
>    As above.

That's fine.

Julien.