Had not Dllimport in D?

[Rikki Cattermole via Digitalmars-d-learn]

Okay, since you clearly have not worked in a native language before, 
lets start from scratch.

You want to make some bindings to a shared library called "msvcrt-ruby18".
 From this I know that it is using the Microsoft Visual C runtime. That 
means you must build D using this as well.
This is done via the -ms32coff switch for 32bit and -m64 for 64bit 
(which is easier all up).
You will need Visual studio with all of the c/c++ stuff installed.
Keep in mind you must match the version of Visual C runtime up with the 
shared libraries one (if you fail enjoy the segfaults!).

Lastly you want some bindings. I won't cover that here. But this should 
help ya out http://dlang.org/spec/interfaceToC.html

After this you should be able to pass the shared library directly to dmd 
when in -ms32coff or -m64 mode and it'll all work.