Allow 64 bit host library to build.

Change-Id: I0911e11d07e314e2ef5ffda187ea345d748c2118
diff --git a/Android.mk b/Android.mk
index 33f9afe..ed3217c 100644
--- a/Android.mk
+++ b/Android.mk
@@ -20,6 +20,9 @@
 ifeq ($(HOST_OS),linux)
 ifeq ($(HOST_ARCH),$(filter $(HOST_ARCH),x86 x86_64))
 build_host := true
+ifneq ($(strip $(BUILD_HOST_64bit)),)
+HOST_ARCH := x86_64
+endif
 endif
 endif