Merge "Better errors from build-flag" into main am: 423b8f68

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/3094708



Change-Id: Iae98b559dc268f52764a4402345f09f0d2f30960
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>