Add android_dlwarning() method

This is temporary method intended to use
for a toast message on preview and beta
releases. Will be removed before the
production release.

Bug: http://b/27365747
Change-Id: I39cc716bb82863ae761b6821bcec77cce6db3781
diff --git a/libdl/libdl.arm64.map b/libdl/libdl.arm64.map
index a8c98da..b3de6bf 100644
--- a/libdl/libdl.arm64.map
+++ b/libdl/libdl.arm64.map
@@ -20,10 +20,15 @@
     dlvsym;
 } LIBC;
 
+LIBC_PLATFORM {
+  global:
+    android_dlwarning;
+} LIBC_N;
+
 LIBC_PRIVATE {
   global:
     android_get_application_target_sdk_version;
     android_set_application_target_sdk_version;
     android_get_LD_LIBRARY_PATH;
     android_update_LD_LIBRARY_PATH;
-} LIBC_N;
+} LIBC_PLATFORM;