databases/sfcgal: fix build with clang 19
Clang 19 now diagnoses incorrect member accesses, which causes
databases/sfcgal to fail with errors similar to:
/wrkdirs/usr/ports/databases/sfcgal/work/CGAL-5.6.1/include/CGAL/boost/graph/iterator.h:219:22: error: no member named 'base' in 'Halfedge_around_source_iterator<Graph>'
219 | return (! (this->base() == nullptr));
| ~~~~ ^
/wrkdirs/usr/ports/databases/sfcgal/work/CGAL-5.6.1/include/CGAL/boost/graph/iterator.h:313:22: error: no member named 'base' in 'Halfedge_around_target_iterator<Graph>'
313 | return (! (this->base() == nullptr));
| ~~~~ ^
/wrkdirs/usr/ports/databases/sfcgal/work/CGAL-5.6.1/include/CGAL/boost/graph/iterator.h:405:22: error: no member named 'base' in 'Halfedge_around_face_iterator<Graph>'
405 | return (! (this->base() == nullptr));
| ~~~~ ^Upstream fixed this in https://github.com/CGAL/cgal/commit/0de060acd68
but it does not apply easily due to some changed context. Add a
backported patch instead.
PR: 280737
Approved by: maintainer timeout (2 weeks)
MFH: 2024Q3
(cherry picked from commit 6a668853ee5c59d92fc9dd6e4d2279d3e5a4eff1)