lib/config, lib/fs: Make junction behaviour configurable (ref #6606) (#6907)

lib/config/migrations.go

@@ -25,6 +25,7 @@ import (
 // update the config version. The order of migrations doesn't matter here,
 // put the newest on top for readability.
 var migrations = migrationSet{
+	{32, migrateToConfigV32},
 	{31, migrateToConfigV31},
 	{30, migrateToConfigV30},
 	{29, migrateToConfigV29},
@@ -91,6 +92,12 @@ func migrateToConfigV31(cfg *Configuration) {
 	cfg.Options.UnackedNotificationIDs = append(cfg.Options.UnackedNotificationIDs, "authenticationUserAndPassword")
 }
 
+func migrateToConfigV32(cfg *Configuration) {
+	for i := range cfg.Folders {
+		cfg.Folders[i].JunctionsAsDirs = true
+	}
+}
+
 func migrateToConfigV30(cfg *Configuration) {
 	// The "max concurrent scans" option is now spelled "max folder concurrency"
 	// to be more general.