update engine: fix gnu++20 build am: 95bc6fb2c8 am: 6888c1ba8a

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

Change-Id: I837d64af139672a8f8607ad355588b8c420d5581
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>