Auto-set arch
diff --git a/build.sh b/build.sh
index 83bfc03..514df05 100755
--- a/build.sh
+++ b/build.sh
@@ -6,7 +6,7 @@
 
 # Now, we check to see that the version env var is set
 ${CPACK_PACKAGE_VERSION:?"Need to set CPACK_PACKAGE_VERSION env var!"}
-${CPACK_DEBIAN_PACKAGE_ARCHITECTURE:?"Need to set CPACK_DEBIAN_PACKAGE_ARCHITECTURE env var!"}
+$CPACK_DEBIAN_PACKAGE_ARCHITECTURE=`dpkg --print-architecture`
 
 # OK, now we get down to the business of building...
 rm -rf ./build