--- a/configure
+++ b/configure
@@ -7054,9 +7054,10 @@
 	   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
+#include <stddef.h>
 #include <comedilib.h>
-main() {
-       comedi_get_cmd_generic_timed(NULL, NULL, NULL, 0, 0);
+void main() {
+       comedi_get_cmd_generic_timed(NULL, 0, NULL, 0, 0);
 }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :