haiku: add as known platform

This combines via CPP two PRs by @jessicah:

- #1217 (for Cabal >= 3.11)
- #1221 (for Cabal <= 3.10)

Author: jessicah

hackage-server.cabal

@@ -130,8 +130,8 @@ common defaults
   -- other dependencies shared by most components
   build-depends:
     , aeson                 ^>= 2.0.3.0 || ^>= 2.1.0.0
-    , Cabal                 ^>= 3.10.1.0
-    , Cabal-syntax          ^>= 3.10.1.0
+    , Cabal                  >= 3.10.1.0 && < 3.12
+    , Cabal-syntax           >= 3.10.1.0 && < 3.12
         -- Cabal-syntax needs to be bound to constrain hackage-security
         -- see https://github.com/haskell/hackage-server/issues/1130
     , fail                  ^>= 4.9.0

src/Distribution/Server/Framework/Instances.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleContexts, BangPatterns, TypeFamilies #-}
 
 {-# OPTIONS_GHC -fno-warn-orphans #-}
@@ -119,6 +120,9 @@ instance SafeCopy VersionRange where
 instance SafeCopy OS where
     errorTypeName _ = "OS"
 
+#if !MIN_VERSION_Cabal_syntax(3,11,0)
+    putCopy (OtherOS "haiku") = contain $ putWord8 18
+#endif
     putCopy (OtherOS s) = contain $ putWord8 0 >> safePut s
     putCopy Linux       = contain $ putWord8 1
     putCopy Windows     = contain $ putWord8 2
@@ -137,6 +141,9 @@ instance SafeCopy OS where
     putCopy Hurd        = contain $ putWord8 15
     putCopy Android     = contain $ putWord8 16
     putCopy Wasi        = contain $ putWord8 17
+#if MIN_VERSION_Cabal_syntax(3,11,0)
+    putCopy Haiku       = contain $ putWord8 18
+#endif
 
     getCopy = contain $ do
       tag <- getWord8
@@ -159,6 +166,11 @@ instance SafeCopy OS where
         15 -> return Hurd
         16 -> return Android
         17 -> return Wasi
+#if MIN_VERSION_Cabal_syntax(3,11,0)
+        18 -> return Haiku
+#else
+        18 -> return $ OtherOS "haiku"
+#endif
         _  -> fail "SafeCopy OS getCopy: unexpected tag"
 
 instance SafeCopy  Arch where
@@ -382,7 +394,13 @@ instance Arbitrary OS where
   arbitrary = oneof [ pure OtherOS <*> vectorOf 3 (choose ('A', 'Z'))
                     , pure Linux, pure Windows, pure OSX, pure FreeBSD
                     , pure OpenBSD, pure NetBSD, pure Solaris, pure AIX
-                    , pure HPUX, pure IRIX, pure HaLVM, pure IOS ]
+                    , pure HPUX, pure IRIX, pure HaLVM, pure IOS
+#if MIN_VERSION_Cabal_syntax(3,11,0)
+                    , pure Haiku
+#else
+                    , pure $ OtherOS "haiku"
+#endif
+                    ]
 
 instance Arbitrary FlagName where
   arbitrary = mkFlagName <$> vectorOf 4 (choose ('a', 'z'))