Fix the LLVM_ENABLE_MODULES build after adding TargetOpcodes.def in r259726.

Differential Revision: http://reviews.llvm.org/D17005

llvm-svn: 260186

llvm/include/llvm/module.modulemap

@@ -37,6 +37,9 @@ module LLVM_Backend {
   module Target {
     umbrella "Target"
     module * { export * }
+
+    // This is intended for (repeated) textual inclusion.
+    textual header "Target/TargetOpcodes.def"
   }
 
   // FIXME: Where should this go?