Export some make variables to soong.variables. am: d637b06d8f am: 02959543d0

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/23305028

Change-Id: Ibeca00ccd1fed1a4c268b1f2efaf3ff5c1ab1976
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>