GDC on Travis-CI

[crimaniak via Digitalmars-d-learn]

I started to work with Travis-CI, building packages using all 
three main compilers, and noticed that I have problems with gdc 
every time and need to tweak code because of many things missing. 
For example: 
https://travis-ci.org/crimaniak/json-patch/jobs/386963340
Why this situation with gdc and how best to deal with it?