semigroup monoid change fallout; drop ghc 7 support

Fix build with ghc 8.4, which broke due to the Semigroup Monoid change.
See https://prime.haskell.org/wiki/Libraries/Proposals/SemigroupMonoid

Dropped support for building propellor with ghc 7 (as in debian
oldstable), to avoid needing to depend on the semigroups transitional
package, but also because it's just too old to be worth supporting.

If we indeed drop ghc 7 support entirely, some code to support "jessie"
can be removed; concurrent-output can be de-embedded, and the Singletons
code can be simplified.

This commit was sponsored by Jack Hill on Patreon.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/Propellor/Property/FreeBSD/Poudriere.hs b/src/Propellor/Property/FreeBSD/Poudriere.hs
index 378c5530..cde2a6d3 100644
--- a/src/Propellor/Property/FreeBSD/Poudriere.hs
+++ b/src/Propellor/Property/FreeBSD/Poudriere.hs
@@ -8,17 +8,18 @@ module Propellor.Property.FreeBSD.Poudriere where
 
 import Propellor.Base
 import Propellor.Types.Info
-import Data.List
-
 import qualified Propellor.Property.FreeBSD.Pkg as Pkg
 import qualified Propellor.Property.ZFS as ZFS
 import qualified Propellor.Property.File as File
 
+import Data.List
+import qualified Data.Semigroup as Sem
+
 poudriereConfigPath :: FilePath
 poudriereConfigPath = "/usr/local/etc/poudriere.conf"
 
 newtype PoudriereConfigured = PoudriereConfigured String
-	deriving (Typeable, Monoid, Show)
+	deriving (Typeable, Sem.Semigroup, Monoid, Show)
 
 instance IsInfo PoudriereConfigured where
 	propagateInfo _ = PropagateInfo False