I had an issue that was discovered to be a bug in gcc (see here: https://github.com/openscad/openscad/issues/882). Applying the patch mentioned here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58800 fixes it.

I've uploaded the patch as applied against the ebuild - it fixes my issue locally.

Copying and pasting my original bug report:

Running Openscad on a very simple model yields me a segmentation fault:

Model:

union()

{ cylinder(r=19,h=10, center=true); }

Command line:

openscad -o test.stl ACylinder.scad
Running in gdb with symbols:

GNU gdb (Gentoo 7.7.1 p1) 7.7.1
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Reading symbols from openscad...done.
(gdb) run
Starting program: /usr/bin/openscad -o test.stl ACylinder.scad
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
operator< (q=..., this=<error reading variable: Cannot access memory at address 0x0>) at /usr/include/CGAL/GMP/Gmpq_type.h:194
194 bool operator< (const Gmpq &q) const

{ return mpq_cmp(this->mpq(), q.mpq()) < 0; }

Full backtrace:

#0 operator< (q=..., this=<error reading variable: Cannot access memory at address 0x0>) at /usr/include/CGAL/GMP/Gmpq_type.h:194
#1 operator() (this=<optimized out>, y=..., x=<error reading variable: Cannot access memory at address 0x0>) at /usr/include/CGAL/Real_embeddable_traits.h:143
#2 compare<CGAL::Gmpq, CGAL::Gmpq> (b=..., a=<error reading variable: Cannot access memory at address 0x0>) at /usr/include/CGAL/number_utils.h:234
#3 operator() (this=<optimized out>, q=..., p=...) at /usr/include/CGAL/Cartesian/function_objects.h:772
#4 compare_y<CGAL::Cartesian<CGAL::Gmpq> > (k=..., q=..., p=...) at /usr/include/CGAL/Kernel/global_functions_internal_3.h:486
#5 compare_y<CGAL::Cartesian<CGAL::Gmpq> > (q=..., p=...) at /usr/include/CGAL/Kernel/global_functions_3.h:424
#6 CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::Smaller_than<CGAL::Cartesian<CGAL::Gmpq>, CGAL::Object, CGAL::internal::In_place_list_iterator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >, std::allocator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >, int>::operator() (this=0x7fffffffa6e0, o1=..., o2=...) at /usr/include/CGAL/Nef_3/K3_tree.h:115
#7 0x00000000005febb8 in _unguarded_partition<gnu_cxx::_normal_iterator<CGAL::Object*, std::vector<CGAL::Object> >, CGAL::Object, CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::Smaller_than<CGAL::Cartesian<CGAL::Gmpq>, CGAL::Object, CGAL::internal::In_place_list_iterator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >, std::allocator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >, int> > (
__comp=..., __pivot=..., __last=..., __first=...) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4.8/bits/stl_algo.h:2263
#8 _unguarded_partition_pivot<gnu_cxx::normal_iterator<CGAL::Object*, std::vector<CGAL::Object> >, CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::Smaller_than<CGAL::Cartesian<CGAL::Gmpq>, CGAL::Object, CGAL::internal::In_place_list_iterator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >, std::allocator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >, int> > (_comp=..., __last=..., __first=...)
at /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4.8/bits/stl_algo.h:2296
#9 std::_introselect<gnu_cxx::_normal_iterator<CGAL::Object*, std::vector<CGAL::Object, std::allocator<CGAL::Object> > >, long, CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::Smaller_than<CGAL::Cartesian<CGAL::Gmpq>, CGAL::Object, CGAL::internal::In_place_list_iterator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >, std::allocator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >, int> > (
__first=..., __nth=..., __nth@entry=..., __last=..., __depth_limit=3, __comp=..., __comp@entry=...) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4.8/bits/stl_algo.h:2394
#10 0x00000000005fedca in nth_element<_gnu_cxx::normal_iterator<CGAL::Object*, std::vector<CGAL::Object> >, CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::Smaller_than<CGAL::Cartesian<CGAL::Gmpq>, CGAL::Object, CGAL::internal::In_place_list_iterator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >, std::allocator<CGAL::SNC_in_place_list_sm<CGAL::SNC_sphere_map<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >, int> > (_comp=..., __last=...,
__nth=..., __first=...) at /usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4.8/bits/stl_algo.h:5417
#11 CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::construct_splitting_plane<int> (this=this@entry=0xb00f90,
start=..., end=..., end@entry=..., median=..., depth=depth@entry=4) at /usr/include/CGAL/Nef_3/K3_tree.h:1246
#12 0x00000000005ff034 in CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::build_kdtree<int> (
this=this@entry=0xb00f90, O=..., v_end=..., depth=depth@entry=4, parent=parent@entry=0xb10e00, non_efective_splits=non_efective_splits@entry=0) at /usr/include/CGAL/Nef_3/K3_tree.h:1130
#13 0x00000000005ff93e in CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::build_kdtree<int> (
this=this@entry=0xb00f90, O=..., v_end=..., depth=depth@entry=3, parent=parent@entry=0xb40d40, non_efective_splits=0, non_efective_splits@entry=1) at /usr/include/CGAL/Nef_3/K3_tree.h:1187
#14 0x00000000005ff93e in CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::build_kdtree<int> (
this=this@entry=0xb00f90, O=..., v_end=..., depth=depth@entry=2, parent=parent@entry=0xb412e0, non_efective_splits=1, non_efective_splits@entry=0) at /usr/include/CGAL/Nef_3/K3_tree.h:1187
#15 0x00000000005ff90e in CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::build_kdtree<int> (
this=this@entry=0xb00f90, O=..., v_end=..., depth=depth@entry=1, parent=parent@entry=0xb01670, non_efective_splits=non_efective_splits@entry=0) at /usr/include/CGAL/Nef_3/K3_tree.h:1186
#16 0x00000000005ff93e in CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::build_kdtree<int> (
this=this@entry=0xb00f90, O=..., v_end=..., depth=depth@entry=0, parent=parent@entry=0x0, non_efective_splits=non_efective_splits@entry=0) at /usr/include/CGAL/Nef_3/K3_tree.h:1187
#17 0x00000000005ffbff in CGAL::K3_tree<CGAL::SNC_k3_tree_traits<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > > >::K3_tree (this=0xb00f90, objects=...,
v_end=...) at /usr/include/CGAL/Nef_3/K3_tree.h:867
#18 0x00000000005fffa9 in CGAL::SNC_point_locator_by_spatial_subdivision<CGAL::SNC_decorator<CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> > >::initialize (this=0xa824e0,
W=<optimized out>) at /usr/include/CGAL/Nef_3/SNC_point_locator.h:415
#19 0x00000000005f31e3 in CGAL::SNC_external_structure_base<int, CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >::create_volumes (this=this@entry=0x7fffffffbcc0)
at /usr/include/CGAL/Nef_3/SNC_external_structure.h:801
#20 0x00000000005f3e7d in create_volumes (this=0x7fffffffbcc0) at /usr/include/CGAL/Nef_3/SNC_external_structure.h:1236
#21 CGAL::SNC_external_structure<CGAL::SNC_indexed_items, CGAL::SNC_structure<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool> >::build_external_structure (this=this@entry=0x7fffffffbcc0)
at /usr/include/CGAL/Nef_3/SNC_external_structure.h:1294
#22 0x00000000005f491b in build_external_structure (this=0xa61e40) at /usr/include/CGAL/Nef_polyhedron_3.h:360
#23 CGAL::Nef_polyhedron_3<CGAL::Cartesian<CGAL::Gmpq>, CGAL::SNC_indexed_items, bool>::Nef_polyhedron_3<CGAL::Cartesian<CGAL::Gmpq>, CGAL::Polyhedron_items_3, CGAL::HalfedgeDS_default, std::allocator<int> > (
this=0xa61e40, P=...) at /usr/include/CGAL/Nef_polyhedron_3.h:568
#24 0x00000000005b20d9 in CGALEvaluator::evaluateCGALMesh (this=this@entry=0x7fffffffcb00, ps=...) at src/CGALEvaluator.cc:693
#25 0x00000000005b2642 in CGALEvaluator::visit (this=0x7fffffffcb00, state=..., node=...) at src/CGALEvaluator.cc:363
#26 0x00000000004b3a5f in Traverser::traverse (this=this@entry=0x7fffffffc680, node=..., state=...) at src/traverser.cc:41
#27 0x00000000004b39c6 in Traverser::traverse (this=this@entry=0x7fffffffc680, node=..., state=...) at src/traverser.cc:30
#28 0x00000000004b39c6 in Traverser::traverse (this=this@entry=0x7fffffffc680, node=..., state=...) at src/traverser.cc:30
#29 0x00000000004b3b87 in Traverser::execute (this=this@entry=0x7fffffffc680) at src/traverser.cc:11
#30 0x00000000005abcdd in CGALEvaluator::evaluateCGALMesh (this=this@entry=0x7fffffffcb00, node=...) at src/CGALEvaluator.cc:44
#31 0x00000000005523b1 in cmdline (deps_output_file=deps_output_file@entry=0x0, filename=..., camera=..., output_file=output_file@entry=0xa3a928 "test.stl", original_path=...,
renderer=renderer@entry=Render::OPENCSG, argc=argc@entry=4, argv=argv@entry=0x7fffffffe4f8) at src/openscad.cc:348
#32 0x0000000000434413 in main (argc=4, argv=0x7fffffffe4f8) at src/openscad.cc:712
It's a Funtoo system, running gcc 4.8.2, under the 3.10.11-1 debian kernel.

Let me know if you need any other information.