Deprecate OpenSL ES for Android API level 30 in Android.mk

Bug: 149721303
Test: try with an NDK r21 canary for both R and earlier, and a pre-21 NDK
Signed-off-by: Tai Kuo <taikuo@google.com>
Change-Id: Ib2c8c2f17a7bbea21e6e7ead13fe3304910e2398
diff --git a/android/WALT/app/src/main/jni/Android.mk b/android/WALT/app/src/main/jni/Android.mk
index 3307036..08d71f2 100644
--- a/android/WALT/app/src/main/jni/Android.mk
+++ b/android/WALT/app/src/main/jni/Android.mk
@@ -20,7 +20,7 @@
 LOCAL_MODULE    := sync_clock_jni
 LOCAL_SRC_FILES := sync_clock_jni.c sync_clock.c player.c
 
-LOCAL_CFLAGS := -g -DUSE_LIBLOG -Werror
+LOCAL_CFLAGS := -g -DUSE_LIBLOG -Werror -Wno-deprecated-declarations
 
 # needed for logcat
 LOCAL_SHARED_LIBRARIES := libcutils