In file included from /home/acxz/vcs/git/github/acxz/flightgear-arch/simgear/src/simgear-2020.3.19/simgear/scene/viewer/Compositor.cxx:17:
/home/acxz/vcs/git/github/acxz/flightgear-arch/simgear/src/simgear-2020.3.19/simgear/scene/viewer/Compositor.hxx:137:34: error: field ‘_uniforms’ has incomplete type ‘simgear::compositor::Compositor::BuiltinUniforms’ {aka ‘std::array<osg::ref_ptr<osg::Uniform>, 14>’}
137 | BuiltinUniforms _uniforms;
| ^~~~~~~~~