rclone special remote

Added rclone special remote, which can be used without needing to install
the git-annex-remote-rclone program. This needs a new version of rclone,
which supports "rclone gitannex".

This is implemented as a variant of an external special remote, that
runs "rclone gitannex" instead of the usual git-annex-remote- command.
Parameterized Remote.External to support that.

Sponsored-by: Luke T. Shumaker on Patreon

Remote/Rclone.hs

@@ -0,0 +1,31 @@
+{- Rclone special remote, using "rclone gitannex"
+ -
+ - Copyright 2024 Joey Hess <id@joeyh.name>
+ -
+ - Licensed under the GNU AGPL version 3 or higher.
+ -}
+
+module Remote.Rclone (remote) where
+
+import Types
+import Types.Remote
+import Remote.Helper.Special
+import Remote.Helper.ExportImport
+import Utility.SafeCommand
+import qualified Remote.External as External
+import Remote.External.Types
+
+remote :: RemoteType
+remote = specialRemoteType $ RemoteType
+	{ typename = "rclone"
+	, enumerate = const (findSpecialRemotes "rclone")
+	, generate = External.gen remote p
+	, configParser = External.remoteConfigParser p
+	, setup = External.externalSetup p setgitconfig 
+	, exportSupported = External.checkExportSupported p
+	, importSupported = importUnsupported
+	, thirdPartyPopulated = False
+	}
+  where
+	p = Just $ ExternalCommand "rclone" [Param "gitannex"]
+	setgitconfig = Just ("rclone", "true")