Make libbacktrace buildable for native_bridge

Bug: http://b/153609531

Test: m -j64 libbacktrace.native_bridge

Change-Id: I2b8a881b4e952f3b68dbcaeb14f147a6d955b406
diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index 3c44534..19c22c8 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -124,6 +124,8 @@
     name: "libunwindstack",
     vendor_available: true,
     recovery_available: true,
+    // TODO(b/153609531): remove when no longer needed.
+    native_bridge_supported: true,
     vndk: {
         enabled: true,
         support_system_process: true,
@@ -145,6 +147,11 @@
             exclude_srcs: ["DexFile.cpp"],
             exclude_shared_libs: ["libdexfile_support"],
         },
+        native_bridge: {
+            cflags: ["-UDEXFILE_SUPPORT"],
+            exclude_srcs: ["DexFile.cpp"],
+            exclude_shared_libs: ["libdexfile_support"],
+        },
     },
 
     apex_available: [