libmedia: fix all warning, make warnings errors, use clang

Change-Id: Ic00d2c5d0bbb1605e96666e25c9ccc22bea6d3ff
diff --git a/media/libmedia/Android.mk b/media/libmedia/Android.mk
index 78baa43..0c18828 100644
--- a/media/libmedia/Android.mk
+++ b/media/libmedia/Android.mk
@@ -7,6 +7,9 @@
 LOCAL_MODULE:= libmedia_helper
 LOCAL_MODULE_TAGS := optional
 
+LOCAL_C_FLAGS += -Werror -Wall
+LOCAL_CLANG := true
+
 include $(BUILD_STATIC_LIBRARY)
 
 include $(CLEAR_VARS)
@@ -84,5 +87,8 @@
     $(call include-path-for, audio-effects) \
     $(call include-path-for, audio-utils)
 
+LOCAL_CFLAGS += -Werror -Wall
+LOCAL_CLANG := true
+
 include $(BUILD_SHARED_LIBRARY)