HACK: add 64-bit directory blacklist

Change-Id: I431e8b220db81d51930dc0b3d95995df120c179a
diff --git a/core/main.mk b/core/main.mk
index 871f51b..ee22a91 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -92,6 +92,8 @@
 # and host information.
 include $(BUILD_SYSTEM)/config.mk
 
+include $(BUILD_SYSTEM)/64_bit_blacklist.mk
+
 # This allows us to force a clean build - included after the config.mk
 # environment setup is done, but before we generate any dependencies.  This
 # file does the rm -rf inline so the deps which are all done below will