--- ./source4/heimdal/lib/krb5/rd_cred.c.orig	2017-03-11 18:20:08.000000000 +0100
+++ ./source4/heimdal/lib/krb5/rd_cred.c	2017-03-11 18:20:02.000000000 +0100
@@ -222,7 +222,7 @@
 
 	if (enc_krb_cred_part.timestamp == NULL ||
 	    enc_krb_cred_part.usec      == NULL ||
-	    abs(*enc_krb_cred_part.timestamp - sec)
+	    labs(*enc_krb_cred_part.timestamp - sec)
 	    > context->max_skew) {
 	    krb5_clear_error_message (context);
 	    ret = KRB5KRB_AP_ERR_SKEW;