Bug#974660: ginkgocadx: FTBFS in sid

[Gianfranco Costamagna]

control: tags -1 patch
control: forwarded -1 https://github.com/gerddie/ginkgocadx/pull/53

https://github.com/gerddie/ginkgocadx/pull/53

I fixed the build failure by adding the missing include, and opened a Pull 
Request upstream.

cheers,

Gianfranco