diff --git a/guile-readline/configure.in b/guile-readline/configure.in
index 9dc7737f0..4c0ae418f 100644
--- a/guile-readline/configure.in
+++ b/guile-readline/configure.in
@@ -112,5 +112,7 @@ AC_SUBST(LIBGUILEREADLINE_INTERFACE_AGE)
 AC_SUBST(LIBGUILEREADLINE_INTERFACE)
 AC_SUBST(LIBGUILEREADLINE_MAJOR)
 
+AC_SUBST(GUILE_EFFECTIVE_VERSION)
+
 AC_CONFIG_FILES(Makefile)
 AC_OUTPUT