Add targets of symlinks to genrule's sources am: f45e673a55 am: 855fa9bd41

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

Change-Id: I56f7b733be05654a455a4c88210a0dab66bd688b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>