Merge "cargo2rulesmk.py: Support customizing rustc" into main am: a3f72f8382 am: 76ebade138 am: 13b5d1261a

Original change: https://android-review.googlesource.com/c/platform/development/+/2726754

Change-Id: Ibe01a1bd5b2645d57b39f151197f72dfc9c8dc4b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>