d++: Error: Could not execute `dmd c.o .\foo.d -offoo.exe`:

[Jack]

I'm trying to get d++ to work on Windows 10/64-bit machine but it 
doesn't work. I'm using the very same code samples c.c, c.h and 
foo.dpp from here 
https://github.com/atilaneves/dpp/tree/master/bash but when I 
went to run:

> d++ foo.dpp c.o

I got the error:

> Error: Could not execute `dmd c.o .\foo.d -offoo.exe`:
> Error: unrecognized file extension o

dmd version:
>DMD32 D Compiler v2.094.1-dirty

gcc version:
>gcc version 6.3.0 (MinGW.org GCC-6.3.0-1)

d++ the least one, build from sources

my OS is windows 10/64-bit. What am I missing?