Disable deprecation warnings in Cabal build

hadrian/src/Settings/Warnings.hs

@@ -51,4 +51,7 @@ ghcWarningsArgs = do
                                       , "-Wno-redundant-constraints"
                                       , "-Wno-orphans" ]
         , package win32        ? pure [ "-Wno-trustworthy-safe" ]
-        , package xhtml        ? pure [ "-Wno-unused-imports" ] ] ]
+        , package xhtml        ? pure [ "-Wno-unused-imports" ] ]
+        , mconcat
+        [ package cabal        ? pure [ "-Wno-error=deprecations" ] ]
+        ]

mk/warnings.mk

@@ -80,6 +80,8 @@ libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports
 libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-redundant-constraints
 libraries/haskeline_dist-install_EXTRA_HC_OPTS += -Wno-simplifiable-class-constraints
 
+# Due to deprecation warning
+libraries/Cabal/Cabal_dist-install_EXTRA_HC_OPTS += -Wno-deprecations
 
 # temporarily turn off unused-imports warnings for pretty
 libraries/pretty_dist-install_EXTRA_HC_OPTS += -Wno-unused-imports