fix warnings and comment

pcbnew/class_pad.cpp

@@ -854,41 +854,39 @@ int D_PAD::Compare( const D_PAD* padref, const D_PAD* padcmp )
 {
     int diff;
 
-    if( diff = padref->m_PadShape - padcmp->m_PadShape) 
+    if( ( diff = padref->m_PadShape - padcmp->m_PadShape ) != 0 )
         return diff;
 
-    if( diff = padref->m_DrillShape - padcmp->m_DrillShape) 
+    if( ( diff = padref->m_DrillShape - padcmp->m_DrillShape ) != 0)
         return diff;
 
-    if( diff = padref->m_Drill.x - padcmp->m_Drill.x )
+    if( ( diff = padref->m_Drill.x - padcmp->m_Drill.x ) != 0 )
         return diff;
 
-    if( diff = padref->m_Drill.y - padcmp->m_Drill.y )
+    if( ( diff = padref->m_Drill.y - padcmp->m_Drill.y ) != 0 )
         return diff;
 
-    if( diff = padref->m_Size.x - padcmp->m_Size.x )
+    if( ( diff = padref->m_Size.x - padcmp->m_Size.x ) != 0 )
         return diff;
 
-    if( diff = padref->m_Size.y - padcmp->m_Size.y )
+    if( ( diff = padref->m_Size.y - padcmp->m_Size.y ) != 0 )
         return diff;
 
-    if( diff = padref->m_Offset.x - padcmp->m_Offset.x )
+    if( ( diff = padref->m_Offset.x - padcmp->m_Offset.x ) != 0 )
         return diff;
 
-    if( diff = padref->m_Offset.y - padcmp->m_Offset.y )
+    if( ( diff = padref->m_Offset.y - padcmp->m_Offset.y ) != 0 )
         return diff;
 
-    if( diff = padref->m_DeltaSize.x - padcmp->m_DeltaSize.x )
+    if( ( diff = padref->m_DeltaSize.x - padcmp->m_DeltaSize.x ) != 0 )
         return diff;
 
-    if( diff = padref->m_DeltaSize.y - padcmp->m_DeltaSize.y ) 
+    if( ( diff = padref->m_DeltaSize.y - padcmp->m_DeltaSize.y ) != 0 )
         return diff;
 
-    // @todo check if export_gencad still works:
-    // specctra_export needs this, but maybe export_gencad does not.
-    // Lorenzo: XXX no idea about specctra, but gencad need it to
-    // implement padstacks!
-    if( diff = padref->m_layerMask - padcmp->m_layerMask )
+    // Dick: specctra_export needs this
+    // Lorenzo: gencad also needs it to implement padstacks!
+    if( ( diff = padref->m_layerMask - padcmp->m_layerMask ) != 0 )
         return diff;
 
     return 0;