On Thu, 09 Oct 2014 21:00:47 +0200, Sönke Ludwig wrote:

That looks strange, those should be standard Phobos symbols.
Unfortunately I don't have a Mac available for testing until next week.
I'll see if I can reproduce the issue then.

As a complete shot in the dark, you could try to add "libs": <br>["phobos2"] to the dub.json of the "testdouble" package. As a sanity
check, does invoking dmd on the following produce any errors? 

import core.thread;
void main()
{
	auto t = Thread.getThis();
	auto f = new Fiber({});
	f.call();
}

I tried this sanity check running dmd 2.066 and get an error message : 

Undefined symbols for architecture x86_64:
  "_D4core6thread5Fiber4callMFbZC6Object", referenced from:
      __Dmain in test.o
  "_D4core6thread6Thread7getThisFZC4core6thread6Thread", referenced from:
      __Dmain in test.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
--- errorlevel 1

So it seems that it's a DMD problem then.