Licensing Question regarding libiberty (LGPL)

I'm checking the license of folly, including depending licenses. Folly itself is Apache 2, but it includes libiberty which is LGPL. This can lead to issues in certain situations, I therefore want to clarify whether building Folly with thde default build options using cmake also links to libiberty.

This is not quite clear to me. Libiberty is looked up in the cmake file, but I'm ot quite sure whether FOLLY_DETAIL_HAVE_DEMANGLE_H is set by default or the no-op implementation is applied in Folly Demangle.