Add a getName accessor for ModuleMacros.

Swift would like to be able to access the name of a ModuleMacro.
There was some discussion of this in
https://github.com/apple/swift-clang/pull/93, suggesting that it makes
sense to have this accessor in Clang.

llvm-svn: 310622

clang/include/clang/Lex/MacroInfo.h

@@ -510,6 +510,9 @@ public:
     ID.AddPointer(II);
   }
 
+  /// Get the name of the macro.
+  IdentifierInfo *getName() const { return II; }
+
   /// Get the ID of the module that exports this macro.
   Module *getOwningModule() const { return OwningModule; }