Cleanup some compiler warnings

eeschema/sch_screen.cpp

@@ -372,7 +372,7 @@ std::set<SCH_ITEM*> SCH_SCREEN::MarkConnections( SCH_LINE* aSegment )
 
 bool SCH_SCREEN::IsJunctionNeeded( const wxPoint& aPosition, bool aNew ) const
 {
-    enum { WIRES = 0, BUSES } layers;
+    enum layers { WIRES = 0, BUSES };
 
     bool                          breakLines[ 2 ] = { false };
     std::unordered_set<int>       exitAngles[ 2 ];

eeschema/symbol_tree_model_adapter.cpp

@@ -101,7 +101,7 @@ void SYMBOL_TREE_MODEL_ADAPTER::AddLibraries( const std::vector<wxString>& aNick
 
     if( loadedSymbols.size() > 0 )
     {
-        for( const std::pair<wxString, std::vector<LIB_PART*>>& pair : loadedSymbols )
+        for( const std::pair<const wxString, std::vector<LIB_PART*>>& pair : loadedSymbols )
         {
             std::vector<LIB_TREE_ITEM*> treeItems( pair.second.begin(), pair.second.end() );
             DoAddLibrary( pair.first, m_libs->GetDescription( pair.first ), treeItems, false );