Let Debian package build without setting extra variables

debian/do-wrapper

@@ -11,8 +11,14 @@ if [[ "${DEB_BUILD_OPTIONS}" =~ nocheck ]]; then
     export NO_TEST=1
 fi
 
-export ADDRESS_PREFIX="${DEB_ADDRESS_PREFIX}"
-export ADDRESS_PREFIX_BITS="${DEB_ADDRESS_PREFIX_BITS}"
+# Pass through prefix overrides if they are set
+if [[ ${DEB_ADDRESS_PREFIX} && ${DEB_ADDRESS_PREFIX-x} ]]; then
+    export ADDRESS_PREFIX="${DEB_ADDRESS_PREFIX}"
+fi
+
+if [[ ${DEB_ADDRESS_PREFIX_BITS} && ${DEB_ADDRESS_PREFIX_BITS-x} ]]; then
+    export ADDRESS_PREFIX_BITS="${DEB_ADDRESS_PREFIX_BITS}"
+fi
 
 # Unset CFLAGS set by debhelper to fix a number of issues.
 # It usually contains something like this: