Use mktemp to create the stdin temporary file.  Not portable to systems
without mktemp, unfortunately.

--- mgetty-1.1.30/fax/faxspool.in	2002-12-18 16:59:16.000000000 -0500
+++ mgetty-1.1.30/fax/faxspool.in	2002-12-18 17:06:43.000000000 -0500
@@ -637,10 +637,14 @@
 #
     if [ x$file = x- ]
     then
+	file=`mktemp /tmp/faxspool.XXXXXX`
+	if test -z $file
+	then
+	    $echo "ERROR: can't create work file, giving up" >&2 ; exit 6
+	fi
+	trap "rm $file" 0
 	$echo "spooling $file (stdin)..."
-	trap "rm /tmp/faxsp.$$" 0
-        cat - >/tmp/faxsp.$$
-	file=/tmp/faxsp.$$
+        cat - >$file
     else
 	$echo "spooling $file..."
     fi