Merge "BPF: Implement build time feature flag for libbpf" into main am: e9d3f9c0ff am: 9801f135b6

Original change: https://android-review.googlesource.com/c/platform/system/bpf/+/3236137

Change-Id: I909547a0c993c3846a4e2b288ca8c424c964f6ca
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>