Fix toolchain issue for windows build of libziparchive.

With mingw 4.8, the new default packed behavior is broken and makes
zip archive fails due to unexpected misalignment in
CentralDirectoryRecord.

This patch uses -mno-ms-bitfields to revert to the old packed
behavior.

Change-Id: Ic977c841e330e19451db1d31ddb22e570a525062
diff --git a/libziparchive/Android.mk b/libziparchive/Android.mk
index 705caa5..d23a94f 100644
--- a/libziparchive/Android.mk
+++ b/libziparchive/Android.mk
@@ -42,6 +42,9 @@
 LOCAL_STATIC_LIBRARIES := libz libutils
 LOCAL_MODULE:= libziparchive-host
 LOCAL_CFLAGS := -Werror
+ifneq ($(strip $(USE_MINGW)),)
+	LOCAL_CFLAGS += -mno-ms-bitfields
+endif
 LOCAL_MULTILIB := both
 include $(BUILD_HOST_STATIC_LIBRARY)