Hyperlynx arcs are always CW

Previous test comparing start/end angles doesn't account for all cases.
This adds a more robust test to ensure all arcs are output in CW fashion

Fixes https://gitlab.com/kicad/code/kicad/issues/10782

pcbnew/exporters/export_hyperlynx.cpp

@@ -480,7 +480,7 @@ bool HYPERLYNX_EXPORTER::writeNetObjects( const std::vector<BOARD_ITEM*>& aObjec
             VECTOR2I       start = arc->GetStart();
             VECTOR2I       end = arc->GetEnd();
 
-            if( arc->GetArcAngleStart() < arc->GetArcAngleEnd() )
+            if( arc->IsCCW() )
                 std::swap( start, end );
 
             m_out->Print( 1, "(ARC X1=%.10f Y1=%.10f X2=%.10f Y2=%.10f XC=%.10f YC=%.10f R=%.10f W=%.10f L=\"%s\")\n",

pcbnew/pcb_track.cpp

@@ -315,6 +315,15 @@ void PCB_ARC::Flip( const VECTOR2I& aCentre, bool aFlipLeftRight )
 }
 
 
+bool PCB_ARC::IsCCW() const
+{
+    VECTOR2I start_end = m_End - m_Start;
+    VECTOR2I start_mid = m_Mid - m_Start;
+
+    return start_end.Cross( start_mid ) < 0;
+}
+
+
 void PCB_VIA::Flip( const VECTOR2I& aCentre, bool aFlipLeftRight )
 {
     if( aFlipLeftRight )

pcbnew/pcb_track.h

@@ -290,6 +290,8 @@ public:
 
     virtual bool HitTest( const EDA_RECT& aRect, bool aContained = true, int aAccuracy = 0 ) const override;
 
+    bool IsCCW() const;
+
     wxString GetClass() const override
     {
         return wxT( "PCB_ARC" );