Your link is failing because the .init value of the struct is not found. The .init will be in the object file corresponding to the module where the struct is defined, so to fix the linker error, add the win32.oaidl module to the list of modules you're compiling and linking. An easy way to do that is to use rdmd instead of dmd to build your program.
Thank you for your prompt reply and maintaining the bindings on GitHub!
I used dub (with dmd). The win32 files reside in another directory and the path is specified in "importPaths". If I understand you correctly, the oaidl.d file should also be specified in "sourceFiles" in the .json file?
