I couldn't find any usage of these extern variables. neither in the file they are defined nor anywhere else in the code
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := tremor
LOCAL_CFLAGS := -I$(LOCAL_PATH) -DHAVE_ALLOCA_H
LOCAL_SRC_FILES = \
tremor/bitwise.c \
tremor/block.c \
tremor/codebook.c \
tremor/floor0.c \
tremor/floor1.c \
tremor/framing.c \
tremor/info.c \
tremor/mapping0.c \
tremor/mdct.c \
tremor/registry.c \
tremor/res012.c \
tremor/sharedbook.c \
tremor/synthesis.c \
tremor/vorbisfile.c \
tremor/window.c
include $(BUILD_STATIC_LIBRARY)