message: re-add error message on failed library load
diff: @@ -117,6 +117,11 @@ namespace ospcommon {
  lib = dlopen(fullName.c_str(), RTLD_NOW | RTLD_GLOBAL);
  }
  #endif
  +
  + if (lib == nullptr) {
  + throw std::runtime_error("could not open module lib " + name + ": " +
  + errorMsg);
  + }
  }
  Library::Library(void *const _lib)
  