diff --git a/configure.ac b/configure.ac
index 034fc34..56d1bd8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -8,6 +8,7 @@ AM_INIT_AUTOMAKE([foreign])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR([lsyncd.c])
 AC_CONFIG_HEADER([config.h])
+AC_USE_SYSTEM_EXTENSIONS
 
 ###
 # Checks for programs.