Revert merge of pull #4845

It breaks the new mingw tests!

See

- https://travis-ci.org/bitcoin/bitcoin/jobs/36845581
- https://travis-ci.org/bitcoin/bitcoin/jobs/36845582

This reverts commit 470590277782cce2fe73275c74523aef59a51eab, 5e2e7fcb99738d9254d4030d53e4f711b2fc5ee0, a25fd6be138ff2bff7e2ad6a1a789db523c0193f.