Fix the LLVM_ENABLE_MODULES build after adding TargetOpcodes.def in r259726

[DavidKreitzer]

Summary

Thanks, Richard, for the advice on how to fix to LLVM_ENABLE_MODULES build. I trust this is what you were suggesting?

I have been unable to test this, because I have not yet been able to get the stage 2 build working in my environment. (That is, the build fails before it hits the error reported by the buildbot.) The change is simple enough, though, that my plan is to just watch the buildbot and verify that it starts working again.

[rsmith]

Yes, thanks.

include/llvm/module.modulemap

module CodeGen {
 
     // These are intended for (repeated) textual inclusion.
     textual header "CodeGen/DIEValue.def"
   }
 
   module Target {
     umbrella "Target"
     module * { export * }
+
+    // This is intended for (repeated) textual inclusion.
+    textual header "Target/TargetOpcodes.def"
   }
 
   // FIXME: Where should this go?
   module Analysis_BlockFrequencyInfoImpl {
     header "Analysis/BlockFrequencyInfoImpl.h"
     export *
   }
 }