With the modified circular dependency detection, thread initialization in DLLs no longer works. This happens because the variable _moduleinfo_tlsdtors_i is used to check whether TLS has been initialized, but it is now declared shared.
Here's a patch that does no longer rely on this variable:
Left file: C:\l\dmd-2.051\src\druntime\src\core\dll_helper.d
Right file: C:\l\dmd-2.051\src\druntime\src\core\dll_helper.org
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< static bool tlsCtorRun;
< static this() { tlsCtorRun = true; }
<
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< if( initTls && !tlsCtorRun ) // avoid duplicate calls
---
> if( initTls && !_moduleinfo_tlsdtors_i ) // avoid duplicate calls