fix adb_test Windows build

adb/Android.mk: adb_test should build on Windows (and Darwin), so add to
the whitelist.

Change-Id: I778f6a7dff4caec92c48e0957591abf32f86ab1b
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>
diff --git a/adb/Android.mk b/adb/Android.mk
index 543f1eb..14e0776 100644
--- a/adb/Android.mk
+++ b/adb/Android.mk
@@ -142,6 +142,7 @@
 
 include $(CLEAR_VARS)
 LOCAL_MODULE := adb_test
+LOCAL_MODULE_HOST_OS := darwin linux windows
 LOCAL_CFLAGS := -DADB_HOST=1 $(LIBADB_CFLAGS)
 LOCAL_CFLAGS_windows := $(LIBADB_windows_CFLAGS)
 LOCAL_CFLAGS_linux := $(LIBADB_linux_CFLAGS)