sysdeps: Add support for vfprintf() logging am: 597efcd89c am: 921eca660f am: a0000e9544 am: de34939838

Original change: https://android-review.googlesource.com/c/platform/external/avb/+/2520439

Change-Id: I73bb2cffd90af80dba12eae359c3d95698b20856
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>