Here's now to build the branch from openscad/openscad#3641 (see full build instructions)
git clone --depth 1 http://github.com/ochafik/openscad --single-branch --branch fast_csg ochafik-openscad
cd ochafik-openscad
rm -fR objects/
qmake openscad.pro \
CONFIG+=debug \
CONFIG+=experimental \
CONFIG+=info \
QMAKE_CXXFLAGS+=-I../CGAL-5.2/include
make -j4
And here's how to trigger a weird corefinement edge-case (or bug?) that leaves a polyhedron in a state we can't build a nef from:
# See output log below
./openscad -o out.stl testdata/scad/3D/features/mirror-tests.scad --enable=fast-csg
I did try and repair the polyhedron with https://gist.github.com/ochafik/e55c52c50804bcb6f073968a57099e63, to no avail.
I can't compile, I'm having:
From the log you provide it seems that the input contains some degenerate faces which Nef and coref seem to complain about. Is it possible?