update engine: fix gnu++20 build am: 95bc6fb2c8 am: dcee10552c

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2834790

Change-Id: I8db28e561d384bbba17a7462cce141d6ecef0dd0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>