Undefined symbol?

[Tofu Ninja via Digitalmars-d-learn]

When I compile my project in release dmd suddenly starts 
complains about missing symbols that look like they are from 
phobos.

Symbol Undefined 
_D3std9exception134__T12errnoEnforceTbVAyaa50_433a5c445c646d64325c77696e646f77735c62696e5c2e2e5cA7E6C89D7777F0A958C3336C905AF5DE

Any idea what is causing it and what a fix might be?