ghc-cabal: Bring back TRANSITIVE_DEP_NAMES

This is still needed by the Shake build system until things have been
reworked to use Cabal directly.

utils/ghc-cabal/Main.hs

@@ -415,6 +415,7 @@ generate directory distdir dll0Modules config_args
                 variablePrefix ++ "_DEP_IPIDS = " ++ unwords dep_ipids,
                 variablePrefix ++ "_DEP_NAMES = " ++ unwords depNames,
                 variablePrefix ++ "_DEP_COMPONENT_IDS = " ++ unwords depLibNames,
+                variablePrefix ++ "_TRANSITIVE_DEP_NAMES = " ++ unwords transitiveDepNames,
                 variablePrefix ++ "_TRANSITIVE_DEP_COMPONENT_IDS = " ++ unwords transitiveDepLibNames,
                 variablePrefix ++ "_INCLUDE_DIRS = " ++ unwords (includeDirs bi),
                 variablePrefix ++ "_INCLUDES = " ++ unwords (includes bi),