diff --git a/filesystem.req b/filesystem.req
index 985749b..76dceee 100755
--- a/filesystem.req
+++ b/filesystem.req
@@ -7,6 +7,10 @@
 # this out and we need a hardcoded list.
 
 sbin_filenames=${1:?}
+
+# Do nothing if the build system is not merged.
+test -L /usr/sbin || exit 0
+
 declare -A "filenames=($(sed 's/.*/["\0"]=1/' <"${sbin_filenames}"))"
 
 while read -r path; do