include direct.h for _mkdir

Bug: 14416410

The new mingw-w64 toolchain x86_64-w64-mingw32-4.8 no longer
declares _mkdir in io.h.

Change-Id: I624b52d2f35db54a7f28df09f997fc883b0f0557
diff --git a/tools/aapt/CacheUpdater.h b/tools/aapt/CacheUpdater.h
index 0e65589..efb2453 100644
--- a/tools/aapt/CacheUpdater.h
+++ b/tools/aapt/CacheUpdater.h
@@ -12,6 +12,9 @@
 #include <sys/stat.h>
 #include <stdio.h>
 #include "Images.h"
+#ifdef HAVE_MS_C_RUNTIME
+#include <direct.h>
+#endif
 
 using namespace android;