Add windows x86_64

Bug: 26957718
Change-Id: I5cfa2f44c27eac0805d21865c45546ed3c2c2103
diff --git a/common/arch.go b/common/arch.go
index 08c570e..ee1cfae 100644
--- a/common/arch.go
+++ b/common/arch.go
@@ -264,6 +264,8 @@
 		Windows interface{} `blueprint:"filter(android:\"arch_variant\")"`
 		// Properties for module variants being built to run on windows x86 hosts
 		Windows_x86 interface{} `blueprint:"filter(android:\"arch_variant\")"`
+		// Properties for module variants being built to run on windows x86_64 hosts
+		Windows_x86_64 interface{} `blueprint:"filter(android:\"arch_variant\")"`
 		// Properties for module variants being built to run on linux or darwin hosts
 		Not_windows interface{} `blueprint:"filter(android:\"arch_variant\")"`
 	}