Os X do NOT support std::optional::value()
PrusaSlicer_OsX_Mojave:
../src/libslic3r/SLA/SupportIslands/ExpandNeighbor.cpp:23:50: error: 'value' is unavailable: introduced in macOS 10.14
../src/libslic3r/SLA/SupportIslands/ParabolaUtils.cpp:92:22: error: no viable conversion from 'const Slic3r::Point' to 'VD::point_type' (aka 'point_data<double>')
VD::point_type source_point = parabola.focus;
^ ~~~~~~~~~~~~~~
../src/libslic3r/SLA/SupportIslands/ParabolaUtils.cpp:39:33: error: no matching constructor for initialization of 'std::vector<VD::point_type>' (aka 'vector<point_data<double> >')
../src/libslic3r/SLA/SupportIslands/ParabolaUtils.cpp:85:33: error: no matching constructor for initialization of 'std::vector<VD::point_type>' (aka 'vector<point_data<double> >')
../src/libslic3r/SLA/SupportIslands/PolygonUtils.cpp:12:10: warning: variable 'is_in_limits' set but not used [-Wunused-but-set-variable]
../src/libslic3r/SLA/SupportIslands/VoronoiGraphUtils.cpp:294:45: warning: unused variable 'success' [-Wunused-variable]
