Index: bzdiff
--- bzdiff.orig	2019-08-10 11:20:12.373121000 +0200
+++ bzdiff	2019-08-10 11:21:04.776212000 +0200
@@ -49,10 +49,15 @@
                 case "$2" in
 	        *.bz2)
 			F=`echo "$2" | sed 's|.*/||;s|.bz2$||'`
+			if type mktemp >/dev/null 2>&1; then
 			tmp=`mktemp "${TMPDIR:-/tmp}"/bzdiff.XXXXXXXXXX` || {
 			      echo 'cannot create a temporary file' >&2
 			      exit 1
 			}
+			else
+				set -C
+				tmp=${TMPDIR-/tmp}/bzdiff.$$
+			fi
                         bzip2 -cdfq "$2" > "$tmp"
                         bzip2 -cdfq "$1" | $comp $OPTIONS - "$tmp"
                         STAT="$?"