fix build with ghc 9.0.1

I was not able to test the whole build because of a very strange
Prelude.chr: bad argument: 469762054
Which I assume is a problem with this version of ghc or the way I was
using stack.

The stack.yaml that builds it used this patch

diff --git a/stack.yaml b/stack.yaml
index 790bffff2..8bcbaa0ec 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,6 +1,6 @@
 flags:
   git-annex:
-    production: true
+    production: false
     assistant: true
     pairing: true
     torrentparser: true
@@ -18,13 +18,15 @@ extra-deps:
 - IfElse-0.85
 - aws-0.22
 - bloomfilter-2.0.1.0
-- filepath-bytestring-1.4.2.1.6
-- git-lfs-1.1.0
-- http-client-restricted-0.0.3
+- filepath-bytestring-1.4.2.1.8
+- git-lfs-1.1.1
+- http-client-restricted-0.0.4
 - network-multicast-0.3.2
 - sandi-0.5
 - torrent-10000.1.1
 - bencode-0.6.1.1
+- base16-bytestring-0.1.1.7
+- base64-bytestring-1.0.0.3
 explicit-setup-deps:
   git-annex: true
-resolver: lts-16.27
+resolver: nightly-2021-09-07

Remote/Glacier.hs

@@ -178,7 +178,7 @@ store' r k b p = go =<< glacierEnv c gc u
 retrieve :: Remote -> Retriever
 retrieve = byteRetriever . retrieve'
 
-retrieve' :: Remote -> Key -> (L.ByteString -> Annex a) -> Annex a
+retrieve' :: forall a. Remote -> Key -> (L.ByteString -> Annex a) -> Annex a
 retrieve' r k sink = go =<< glacierEnv c gc u
   where
 	c = config r