The following enums:

linkResolver.hpp - class LinkInfo

  enum AccessCheck {
    needs_access_check,
    skip_access_check
  };

klass.hpp - class Klass

  enum DefaultsLookupMode { find_defaults, skip_defaults };
  enum OverpassLookupMode { find_overpass, skip_overpass };
  enum StaticLookupMode   { find_static,   skip_static };
  enum PrivateLookupMode  { find_private,  skip_private };

Should be changed to C++11 enum class to provide better type safety.  Current implementation allows for the enums to be incorrectly compared to boolean true or false.