Mark as recovery_available: true

Libraries that are direct or indirect dependencies of modules installed
to recovery partition (e.g. toybox) are marked as recovery_available:
true. This allows a recovery variant of the lib is created when it is
depended by other recovery or recovery_available modules.

Bug: 67916654
Bug: 64960723
Test: m -j
Change-Id: Ie59155c08890e96ce1893fa3687afcf763d7aea3
diff --git a/libbacktrace/Android.bp b/libbacktrace/Android.bp
index 11b8144..65145c2 100644
--- a/libbacktrace/Android.bp
+++ b/libbacktrace/Android.bp
@@ -51,6 +51,7 @@
 cc_library_headers {
     name: "libbacktrace_headers",
     vendor_available: true,
+    recovery_available: true,
     export_include_dirs: ["include"],
 }