foliadiff speedup: run 2 folialint's in parallel

src/foliadiff.sh

@@ -40,20 +40,21 @@ if [ $# -ne 2 ]
       exit 1
 fi
 
+run_lint(){
+    $exe --strip --KANON "$1" --output $2
+    if [ $? -ne 0 ]
+    then
+	echo "foliadiff.sh: $1 is INVALID FoLiA"
+	exit 1
+    fi
+}
+
 t1=/tmp/${1##*/}.s1
 t2=/tmp/${2##*/}.s2
-$exe --strip --KANON "$1" --output $t1
-if [ $? -ne 0 ]
-then
-    echo "foliadiff.sh: $1 is INVALID FoLiA"
-    exit 1
-fi
-$exe --strip --KANON "$2" --output $t2
-if [ $? -ne 0 ]
-then
-    echo "foliadiff.sh: $2 is INVALID FoLiA"
-    exit 1
-fi
+
+run_lint $1 $t1 &
+run_lint $2 $t2 &
+wait
 diff $t1 $t2
 if [ $? -ne 0 ]
 then