fix: guard Config/Interpreter.hs with HAVE_INTERPRETER

When building without interpreter support (-interpreter flag),
InterpOpts is a stub empty data type without any fields. The
initInterpOpts function was trying to use all 20+ InterpOpts fields
unconditionally, causing build failures.

This fix makes the entire module conditional on HAVE_INTERPRETER:
- When defined: full implementation creating InterpOpts with all fields
- When not defined: stub that returns empty InterpOpts

This allows stage1 minimal builds (without interpreter) to complete
successfully.

Author: angerman

compiler/GHC/Driver/Config/Interpreter.hs

@@ -1,8 +1,12 @@
+{-# LANGUAGE CPP #-}
+
 module GHC.Driver.Config.Interpreter
   ( initInterpOpts
   )
 where
 
+#if defined(HAVE_INTERPRETER)
+
 import GHC.Prelude
 import GHC.Runtime.Interpreter.Init
 import GHC.Driver.DynFlags
@@ -44,3 +48,15 @@ initInterpOpts dflags = do
     , interpExecutableLinkOpts = initExecutableLinkOpts dflags
     }
 
+#else
+-- Stub version when HAVE_INTERPRETER is not defined
+
+import GHC.Prelude
+import GHC.Runtime.Interpreter.Init (InterpOpts(..))
+import GHC.Driver.Session (DynFlags)
+
+-- | Stub initInterpOpts - returns empty InterpOpts when interpreter is disabled
+initInterpOpts :: DynFlags -> IO InterpOpts
+initInterpOpts _ = pure InterpOpts
+
+#endif