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

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

Change-Id: I57bd417abb764e79fdb7981b9cb63a88c0f2b183
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>