Fix incorrect usage of a UTF8 char in a C string in code.

Using a UTF8 char inside a C string can work on unix, but not on Windows.
It must be explicitly converted in a unicode value inside a wide string
(like a wxString)

common/lib_tree_model_adapter.h

@@ -336,6 +336,16 @@ protected:
                   unsigned int            aCol,
                   wxDataViewItemAttr&     aAttr ) const override;
 
+    /**
+     * @return a unicode string to mark a node name like
+     * a pinned library name
+     * This is not an ascii7 char, but a unicode char
+     */
+    const wxString GetPinningSymbol() const
+    {
+        return wxString::FromUTF8( "☆ " );
+    }
+
 private:
     EDA_BASE_FRAME*         m_parent;
 

eeschema/symbol_tree_synchronizing_adapter.cpp

@@ -216,7 +216,7 @@ void SYMBOL_TREE_SYNCHRONIZING_ADAPTER::GetValue( wxVariant& aVariant, wxDataVie
         aVariant = node->m_Name;
 
         if( node->m_Pinned )
-            aVariant = "☆ " + node->m_Name;
+            aVariant = GetPinningSymbol() + node->m_Name;
 
         // mark modified libs with an asterisk
         if( node->m_Type == LIB_TREE_NODE::LIB && m_libMgr->IsLibraryModified( node->m_Name ) )

pcbnew/fp_tree_synchronizing_adapter.cpp

@@ -184,7 +184,7 @@ void FP_TREE_SYNCHRONIZING_ADAPTER::GetValue( wxVariant& aVariant, wxDataViewIte
                 aVariant = currentFPName;
         }
         else if( node->m_Pinned )
-            aVariant = "☆ " + node->m_Name;
+            aVariant = GetPinningSymbol() + node->m_Name;
         else
             aVariant = node->m_Name;
         break;