Eagle octagonal pads are regular (~29% chamfered).

Also cleans up setting of KeepTopBottom (which is ignored unless
we're doing optional flahing -- which we're not for Eagle imports).

Fixes https://gitlab.com/kicad/code/kicad/issues/11664

pcbnew/plugins/eagle/eagle_plugin.cpp

@@ -1894,8 +1894,7 @@ void EAGLE_PLUGIN::packageWire( FOOTPRINT* aFootprint, wxXmlNode* aTree ) const
         }
     }
 
-    // FIXME: the cap attribute is ignored because KiCad can't create lines
-    //        with flat ends.
+    // FIXME: the cap attribute is ignored because KiCad can't create lines with flat ends.
     FP_SHAPE* dwg;
 
     if( !w.curve )
@@ -1941,8 +1940,6 @@ void EAGLE_PLUGIN::packagePad( FOOTPRINT* aFootprint, wxXmlNode* aTree )
     else if( aFootprint->GetLayer() == B_Cu && m_rules->psBottom != EPAD::UNDEF )
         shape = m_rules->psBottom;
 
-    pad->SetKeepTopBottom( false ); // TODO: correct? This seems to be KiCad default on import
-
     pad->SetDrillSize( wxSize( eagleDrillz, eagleDrillz ) );
     pad->SetLayerSet( LSET::AllCuMask() );
 
@@ -1965,12 +1962,9 @@ void EAGLE_PLUGIN::packagePad( FOOTPRINT* aFootprint, wxXmlNode* aTree )
             break;
 
         case EPAD::OCTAGON:
-            // no KiCad octagonal pad shape, use PAD_CIRCLE for now.
-            // pad->SetShape( PAD_OCTAGON );
-            wxASSERT( pad->GetShape() == PAD_SHAPE::CIRCLE );    // verify set in PAD constructor
             pad->SetShape( PAD_SHAPE::CHAMFERED_RECT );
             pad->SetChamferPositions( RECT_CHAMFER_ALL );
-            pad->SetChamferRectRatio( 0.25 );
+            pad->SetChamferRectRatio( 1 - M_SQRT1_2 );    // Regular polygon
             break;
 
         case EPAD::LONG:
@@ -2007,8 +2001,7 @@ void EAGLE_PLUGIN::packagePad( FOOTPRINT* aFootprint, wxXmlNode* aTree )
 
     if( pad->GetShape() == PAD_SHAPE::OVAL )
     {
-        // The Eagle "long" pad is wider than it is tall,
-        // m_elongation is percent elongation
+        // The Eagle "long" pad is wider than it is tall; m_elongation is percent elongation
         VECTOR2I sz = pad->GetSize();
         sz.x = ( sz.x * ( 100 + m_rules->psElongationLong ) ) / 100;
         pad->SetSize( sz );