Add mkuserimg.sh script for the build system

Change-Id: I74b41e5d783646b51203423a7deabbdb28b32b7b
diff --git a/ext4_utils/Android.mk b/ext4_utils/Android.mk
index d8a20f9..3f8b10e 100644
--- a/ext4_utils/Android.mk
+++ b/ext4_utils/Android.mk
@@ -60,3 +60,15 @@
 LOCAL_STATIC_LIBRARIES += libext4_utils libz
 
 include $(BUILD_HOST_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := mkuserimg.sh
+LOCAL_SRC_FILES := mkuserimg.sh
+LOCAL_MODULE_CLASS := EXECUTABLES
+# We don't need any additional suffix.
+LOCAL_MODULE_SUFFIX :=
+LOCAL_BUILT_MODULE_STEM := $(notdir $(LOCAL_SRC_FILES))
+LOCAL_IS_HOST_MODULE := true
+
+include $(BUILD_PREBUILT)