Fixed CheckMacroPass pass to work correctly for declaration contexts.

This has been broken since we started parsing preprocessed entities for all declarations. In the specific cases of declaration contexts (translation units and namespaces) we would be processing child declaration preprocessed entities and ignoring the whole contexts by mistake.

src/Generator/Passes/CheckMacrosPass.cs

@@ -45,6 +45,9 @@ namespace CppSharp.Passes
             if (AlreadyVisited(decl))
                 return false;
 
+            if (decl is DeclarationContext)
+                return true;
+
             var expansions = decl.PreprocessedEntities.OfType<MacroExpansion>();
 
             if (expansions.Any(e => e.Text == Prefix + "_IGNORE" &&