"make std/concurrency.test" fails but others don't... why?

[Martin Nowak via Digitalmars-d]

On 04/11/2015 01:04 AM, Andrei Alexandrescu wrote:
> What makes MessageBox special?
> 
> 
> Andrei

For some reason the linker drags in another copy of the concurrency
module (part of it to be precise concurrency_329_3ee.o).
That collides with concurrency.o the to be tested module.

I don't have time to debug this on OSX, but looking at the verbose
linker output or at the symbols in both object files might give you an
idea, why it was pulled in.

ar x generated/osx/release/64/libphobos2.a concurrency_329_3ee.o
nm concurrency_329_3ee.o

../dmd/src/dmd -conf= -I../druntime/import  -w -dip25 -m64  -O -release
-main -unittest -c std/concurrency.d
nm concurrency.o | grep ' U '

It's probably because of some undefined ModuleInfoZ or InitZ symbol in
the concurrency.o object.