Add support for writing a gzip compressed image

Change-Id: Ica2ff90060f6a4ced2c671084205b58eede66cdf
diff --git a/ext4_utils/Android.mk b/ext4_utils/Android.mk
index c8bda90..819e634 100644
--- a/ext4_utils/Android.mk
+++ b/ext4_utils/Android.mk
@@ -8,6 +8,7 @@
         ext_utils.c \
         allocate.c \
         backed_block.c \
+        output_file.c \
         contents.c \
         extent.c \
         indirect.c \
@@ -17,6 +18,8 @@
 LOCAL_SRC_FILES := $(make_ext4fs_src_files)
 LOCAL_MODULE := make_ext4fs
 LOCAL_MODULE_TAGS := optional
+LOCAL_C_INCLUDES += external/zlib
+LOCAL_SHARED_LIBRARIES += libz
 
 include $(BUILD_EXECUTABLE)
 
@@ -24,5 +27,6 @@
 
 LOCAL_SRC_FILES := $(make_ext4fs_src_files)
 LOCAL_MODULE := make_ext4fs
+LOCAL_STATIC_LIBRARIES += libz
 
 include $(BUILD_HOST_EXECUTABLE)