DXF and DWG: fix linear approximation of circular and elliptic arc in HATCH boundaries (patch by ermite, #5182)

git-svn-id: https://svn.osgeo.org/gdal/trunk@26672 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' into trunk_travis_macosx