--- au.c.orig	Wed Aug  3 22:13:29 1994
+++ au.c	Thu Apr 24 13:37:59 1997
@@ -299,6 +299,8 @@
 	wblong(ft, magic);
 
 	/* hdr_size = SUN_HDRSIZE;		/* + strlen(ft->comment); */
+	if (ft->comment == NULL)
+		ft->comment = "";
 	hdr_size = SUN_HDRSIZE + strlen(ft->comment);
 	wblong(ft, hdr_size);