--- lkc.h.orig	2014-05-21 11:35:33.210489800 +0200
+++ lkc.h	2014-05-21 11:35:33.210489800 +0200
@@ -90,7 +90,10 @@ struct conf_printer {
 /* confdata.c and expr.c */
 static inline void xfwrite(const void *str, size_t len, size_t count, FILE *out)
 {
-	assert(len != 0);
+	/*assert(len != 0);*/
+	if (len==0) {
+		return;
+	}
 
 	if (fwrite(str, len, count, out) != count)
 		fprintf(stderr, "Error in writing or end of file.\n");