DMD Refuses to Compile Multiple Source Files

[Samwise via Digitalmars-d-learn]

On Wednesday, 18 January 2017 at 02:48:45 UTC, James Buren wrote:
> Import the source file containing the external function instead 
> of writing that prototype. It should compile then.

This seems like a workaround more than a permanent solution. It 
would work, but still. I'm also not sure about the syntax for 
that (Given that getReturnCode.d is in the same directory as 
hello.d).
~Sam