Function get_segment_intersect_pt 

pub fn get_segment_intersect_pt(
    ln1a: Point64,
    ln1b: Point64,
    ln2a: Point64,
    ln2b: Point64,
    ip: &mut Point64,
) -> bool

Calculate exact intersection point between two line segments for Point64 Direct port from clipper.core.h line 902 - simplified version for i64 coordinates