diff --git a/openbsc/m4/README b/openbsc/m4/README
new file mode 100644
index 0000000..92eb30b
--- /dev/null
+++ b/openbsc/m4/README
@@ -0,0 +1,3 @@
+We want to avoid creating too many external build-time dependencies
+like this one to autoconf-archive.  This directory provides a local
+copy of required m4 rules.