diff --git a/configure.ac b/configure.ac
index d42d881c..c13698d1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -185,7 +185,7 @@ PKG_CHECK_MODULES([ICU], [icu-uc], [
 		CPPFLAGS="$old_CPPFLAGS"
 		LIBS="$old_LIBS",
 	)
-],)
+], [])
 
 dnl =============================
 dnl = checking for boost.thread =