Mark libsync as LL-NDK

libsync is used both by platform (e.g. libui.so) and by same-process
HALs (e.g. android.hardware.graphics.mapper@2.0-impl.so). Therefore it
is eligible for either VNDK-SP or LL-NDK. Among the two choices, LL-NDK
was selected because it is already an NDK and is just a thin wrapper
around a few kernel ioctls.

However, since libui (which is a vendor_available:true library) is using
more symbols that are not available to NDK clients, the extra symbols
are exposed as # vndk tag so that they are only available to VNDK
clients, but not to NDK clients.

Bug: 63866913
Test: BOARD_VNDK_VERSION=current m -j successful (2017 pixel)
Test: the built image is bootable
Merged-In: I60f883c049bd9b4562e6ce34d34ead47ba28af5f
Change-Id: I60f883c049bd9b4562e6ce34d34ead47ba28af5f
(cherry picked from commit 058e0919f6aff67d32d00591a7040fc069c6e40f)
diff --git a/libsync/Android.bp b/libsync/Android.bp
index 1646348..3fae5e6 100644
--- a/libsync/Android.bp
+++ b/libsync/Android.bp
@@ -22,10 +22,15 @@
 
 cc_library_shared {
     name: "libsync",
-    vendor_available: true,
     defaults: ["libsync_defaults"],
 }
 
+llndk_library {
+    name: "libsync",
+    symbol_file: "libsync.map.txt",
+    export_include_dirs: ["include"],
+}
+
 // libsync_recovery is only intended for the recovery binary.
 // Future versions of the kernel WILL require an updated libsync, and will break
 // anything statically linked against the current libsync.