Add a library to wrap libfiemap differences between recovery and normal AOSP.

libsnapshot has to work both in normal boot and in recovery. Normally,
we want libfiemap to be used through gsid, via binder, to consolidate the
necessary SELinux permissions. However binder is not available in
recovery, so instead we introduce a compile-time abstraction layer.

Recovery should link to libfiemap; otherwise, libfiemap_binder
should be used instead. They both present the same API.

Bug: 134536978
Test: manual test
Change-Id: I60370af2175723141e61f0ee301cad40d2f331c1
9 files changed