I'm running this on Windows 10 with still plenty of disk space:

I git cloned this repository into a local directory and then copied Oracle 12.1.0.2 Enterprise Edition for Linux into /c/Users/lukas/docker/oracle/docker-images/OracleDatabase/dockerfiles/12.1.0.2 and then ran buildDockerImage.sh only to get a "no space left on device" error

What might be the cause of this?
You will have to dig configuration of Docker Toolbox for Windows. It uses a VirtualBox VM behind the scenes. That is where I believe disk space is not sufficient, not your host (Windows).
Also make sure that your base image size is big enough. For Oracle Database EE the default 10G aren't enough:

On Linux I had to set --storage-opt dm.basesize to a higher value in /etc/sysconfig/docker-storage:

@lukaseder, I don't think there is anything we can do in the Dockerfiles to fix this. It is up to the user to adjust its Docker installation and host environment
Thanks for your help. I was afraid I had to dig into how these things work in detail :) (first time docker user here, believe it or not)
OK, for the record (i.e. for other docker newbies like myself), this is the command to increase the default disk (and memory) size:
$ docker-machine create --driver virtualbox --virtualbox-disk-size "40000" --virtualbox-memory 2048 default
That did the trick for my particular issue. Might be a useful addition to the setup instructions here: https://github.com/oracle/docker-images/blob/master/OracleDatabase/README.md
The default machine created by Docker Toolbox for first time dummies like me has much less disk space and memory. Might be a nice time saver for others
Folks: Just wanted to say that this is _really excellent_. Thanks a lot for doing this. Will definitely advertise this to everyone, also on the jOOQ blog :)
We are glad to hear @lukaseder and appreciate the valuable feedback! Have fun dockering around :)
Most helpful comment
OK, for the record (i.e. for other docker newbies like myself), this is the command to increase the default disk (and memory) size:
That did the trick for my particular issue. Might be a useful addition to the setup instructions here: https://github.com/oracle/docker-images/blob/master/OracleDatabase/README.md
The default machine created by Docker Toolbox for first time dummies like me has much less disk space and memory. Might be a nice time saver for others