diff --git a/server/config.m4 b/server/config.m4
index 631d5a3756..2f1598068e 100644
--- a/server/config.m4
+++ b/server/config.m4
@@ -56,6 +56,5 @@ fi
 dnl ## Check for library functions
 
 AC_CHECK_FUNCS(
-difftime \
 syslog \
 )