[pkg-fgfs-crew] Bug#793517: Bug#793517: fltk1.3-dev cmake interface now requires libcairo2-dev and fluid?

[Rebecca N. Palmer]

It's lmms that isn't finding fluid (because it doesn't build-depend on 
it), fgrun is only missing libcairo2-dev.

However, fgrun already bypasses cmake-data with
     find_package(FLTK REQUIRED NO_MODULE)
as recommended in 
https://sources.debian.net/src/fltk1.3/1.3.3-2/README.CMake.txt/#L233 
and required to use FLTK as a shared library; packages that don't may 
well hit #793549 as well.