Merge "Add Soong config variable for libgbm build variants" into main am: 5beb9a4475

Original change: https://android-review.googlesource.com/c/platform/external/minigbm/+/3255521

Change-Id: I027c95b7136eb3214f5e74d91536530d19c6d84d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>