diff --git a/guile-readline/configure.in b/guile-readline/configure.in
index c2056712c..41661713a 100644
--- a/guile-readline/configure.in
+++ b/guile-readline/configure.in
@@ -126,5 +126,7 @@ AC_SUBST(LIBGUILEREADLINE_INTERFACE_REVISION)
 AC_SUBST(LIBGUILEREADLINE_INTERFACE_AGE)
 AC_SUBST(LIBGUILEREADLINE_INTERFACE)
 
+AC_SUBST(GUILE_EFFECTIVE_VERSION)
+
 AC_CONFIG_FILES(Makefile)
 AC_OUTPUT