Eeschema: allow auto-wiring from zero-length pins (e.g. power symbols)

eeschema/sch_component.cpp

@@ -1876,3 +1876,11 @@ void SCH_COMPONENT::ClearBrightenedPins()
 }
 
 
+bool SCH_COMPONENT::IsPointClickableAnchor( const wxPoint& aPos ) const
+{
+    for( auto& pin : m_pins )
+        if( pin->IsPointClickableAnchor( aPos ) )
+            return true;
+
+    return false;
+}

eeschema/sch_component.h

@@ -687,6 +687,8 @@ public:
     bool GetIncludeOnBoard() const { return m_onBoard; }
     void SetIncludeOnBoard( bool aIncludeOnBoard ) { m_onBoard = aIncludeOnBoard; }
 
+    bool IsPointClickableAnchor( const wxPoint& aPos ) const override;
+
 private:
     bool doIsConnected( const wxPoint& aPosition ) const override;
 };