Add targets of symlinks to genrule's sources am: f45e673a55

Original change: https://android-review.googlesource.com/c/platform/external/libcxx/+/2853249

Change-Id: I6f872a5454a7d8e5e41f651d37a9ce77d55f25f8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>