Deprecate OpenSL ES for Android as of API level 30 (R)

Cherry-pick from the master branch to prevent merge conflicts.

Bug: 149721303
Test: try with an NDK r21 canary for both R and earlier, and a pre-21 NDK
Change-Id: Ie0a317debd07230d344218c5874f3060dc3ab85f
Merged-In: Ie0a317debd07230d344218c5874f3060dc3ab85f
diff --git a/android/WALT/app/src/main/jni/Android.bp b/android/WALT/app/src/main/jni/Android.bp
index a789f4b..cbbaa82 100644
--- a/android/WALT/app/src/main/jni/Android.bp
+++ b/android/WALT/app/src/main/jni/Android.bp
@@ -25,6 +25,7 @@
         "-g",
         "-DUSE_LIBLOG",
         "-Werror",
+        "-Wno-deprecated-declarations",
     ],
 
     shared_libs: [