Adding upstream version 3.10.8.

Signed-off-by: Daniel Baumann <daniel@debian.org>

util/file.go

@@ -0,0 +1,20 @@
+// Copyright Earl Warren <contact@earl-warren.org>
+// Copyright Loïc Dachary <loic@dachary.org>
+// SPDX-License-Identifier: MIT
+
+package util
+
+import (
+	"os"
+)
+
+func FileExists(pathname string) bool {
+	_, err := os.Stat(pathname)
+	if err == nil {
+		return true
+	}
+	if os.IsNotExist(err) {
+		return false
+	}
+	panic(err)
+}