Mark the module as VNDK or VNDK-SP in Android.bp

As a VNDK/VNDK-SP module, Android.bp must have 'vndk' tag as well
as 'vendor_available: true'.

For a VNDK module, the 'vndk' tag has 'enabled: true'.
It will be installed system/lib(64)/vndk as a vendor variant.

For a VNDK-SP module, the 'vndk' tag has
'support_system_process: true' as well as 'enabled: true'.
It will be installed system/lib(64)/vndk-sp as a vendor variant.

Bug: 63866913
Test: build and boot with BOARD_VNDK_VERSION=current
Merged-In: I4517a3995efa91afb7fa21cdc0bc0fb8b088149b
Change-Id: I4517a3995efa91afb7fa21cdc0bc0fb8b088149b
(cherry picked from commit 50103091feb278697c922c91e097e924753fef9a)
diff --git a/Android.bp b/Android.bp
index 95d9cd3..8e39004 100644
--- a/Android.bp
+++ b/Android.bp
@@ -124,6 +124,10 @@
 cc_library {
     name: "libunwind",
     defaults: ["libunwind_defaults"],
+    vndk: {
+        enabled: true,
+        support_system_process: true,
+    },
     sdk_version: "21",
     stl: "none",