img2simg: Drop using endian.h

All our hosts are currently little-endian, so drop using endian.h
in favor of being able to build and run on all hosts.

Change-Id: Iea86cf9387940448c9c6d356c7e16acc871d5467
Signed-off-by: Scott Anderson <saa@android.com>
diff --git a/ext4_utils/Android.mk b/ext4_utils/Android.mk
index f09197c..9e1e29c 100644
--- a/ext4_utils/Android.mk
+++ b/ext4_utils/Android.mk
@@ -104,16 +104,13 @@
 
 include $(BUILD_EXECUTABLE)
 
-ifeq ($(HOST_OS),linux)
-# Darwin doesn't have endian.h, and img2simg is just a convenience
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES := img2simg.c
 LOCAL_MODULE := img2simg
-LOCAL_MODULE_TAGS := optional
+LOCAL_MODULE_TAGS := debug
 
 include $(BUILD_HOST_EXECUTABLE)
-endif
 
 include $(CLEAR_VARS)