Removed unused variable macro usage

Note: On host toolchains, __unused doesnt seem to be present. Hence
updated all instances to use __attribute__((unused)) instead. Also
unused variables have been deprecated and code has been updated
to use br.skipBits() instead.

Test: Build libstagefright_foundation on Android
Bug: 151789258

Change-Id: Ia2af1467803f3325aa838c8d57809790d5ce19a0
diff --git a/media/libstagefright/foundation/avc_utils.cpp b/media/libstagefright/foundation/avc_utils.cpp
index e8a6083..8605925 100644
--- a/media/libstagefright/foundation/avc_utils.cpp
+++ b/media/libstagefright/foundation/avc_utils.cpp
@@ -546,11 +546,9 @@
     CHECK_NE(video_object_type_indication,
              0x21u /* Fine Granularity Scalable */);
 
-    unsigned video_object_layer_verid __unused;
-    unsigned video_object_layer_priority __unused;
     if (br.getBits(1)) {
-        video_object_layer_verid = br.getBits(4);
-        video_object_layer_priority = br.getBits(3);
+        br.skipBits(4); //video_object_layer_verid
+        br.skipBits(3); //video_object_layer_priority
     }
     unsigned aspect_ratio_info = br.getBits(4);
     if (aspect_ratio_info == 0x0f /* extended PAR */) {
@@ -609,7 +607,7 @@
     unsigned video_object_layer_height = br.getBits(13);
     CHECK(br.getBits(1));  // marker_bit
 
-    unsigned interlaced __unused = br.getBits(1);
+    br.skipBits(1); // interlaced
 
     *width = video_object_layer_width;
     *height = video_object_layer_height;
@@ -655,7 +653,7 @@
         return false;
     }
 
-    unsigned protection __unused = (header >> 16) & 1;
+    // we can get protection value from (header >> 16) & 1
 
     unsigned bitrate_index = (header >> 12) & 0x0f;
 
diff --git a/media/libstagefright/foundation/include/media/stagefright/foundation/ADebug.h b/media/libstagefright/foundation/include/media/stagefright/foundation/ADebug.h
index ab17a02..e4b99bf 100644
--- a/media/libstagefright/foundation/include/media/stagefright/foundation/ADebug.h
+++ b/media/libstagefright/foundation/include/media/stagefright/foundation/ADebug.h
@@ -148,7 +148,8 @@
     static char *GetDebugName(const char *name);
 
     inline static bool isExperimentEnabled(
-            const char *name __unused /* nonnull */, bool allow __unused = true) {
+            const char *name __attribute__((unused)) /* nonnull */,
+            bool allow __attribute__((unused)) = true) {
 #ifdef ENABLE_STAGEFRIGHT_EXPERIMENTS
         if (!strcmp(name, "legacy-adaptive")) {
             return getExperimentFlag(allow, name, 2, 1); // every other day