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

Bug: 134958169
Test: try with an NDK r21 canary for both R and earlier, and a pre-21 NDK
Change-Id: Ie0a317debd07230d344218c5874f3060dc3ab85f
diff --git a/cmds/bootanimation/Android.bp b/cmds/bootanimation/Android.bp
index 3e5877b..befb67b 100644
--- a/cmds/bootanimation/Android.bp
+++ b/cmds/bootanimation/Android.bp
@@ -41,6 +41,10 @@
     ],
 
     init_rc: ["bootanim.rc"],
+
+    cflags: [
+        "-Wno-deprecated-declarations",
+    ],
 }
 
 // libbootanimation