dmd and string imports on Windows

[Atila Neves via Digitalmars-d-learn]

On Linux:

foo.d:
import std.stdio;
void main() { writeln(import("dir/bar.txt")); }

dmd -J. foo.d # ok

On Windows:

Error: file "dir/bar.txt" cannot be found or not in a path 
specified with -J

I tried the obvious buildPath("dir", "bar.txt") instead and now:

Error: file "dir\\bar.d" cannot be found or not in a path 
specified with -J

I tried r"dir\bar.txt" and "dir\\bar.txt" and still nothing. What 
am I supposed to do? Thanks,

Atila