Merge commit '63cb372' into v3-porting

flag.go

@@ -15,6 +15,8 @@ import (
 
 const defaultPlaceholder = "value"
 
+var defaultSliceFlagSeparator = ","
+
 var (
 	slPfx = fmt.Sprintf("sl:::%d:::", time.Now().UTC().UnixNano())
 
@@ -385,5 +387,5 @@ func flagFromEnvOrFile(envVars []string, filePath string) (value string, fromWhe
 }
 
 func flagSplitMultiValues(val string) []string {
-	return strings.Split(val, ",")
+	return strings.Split(val, defaultSliceFlagSeparator)
 }