Passing integer 0 in for a pointer value doesn't work on IA64. Fix this

by using a new macro.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14863 91177308-0d34-0410-b5e6-96231b3b80d8

utils/TableGen/TableGen.cpp

@@ -64,7 +64,7 @@ namespace {
                                "Print enum values for a class"),
                     clEnumValN(Parse, "parse",
                                "Interpret machine code (testing only)"),
-                    0));
+                    clEnumValEnd));
 
   cl::opt<std::string>
   Class("class", cl::desc("Print Enum list for this class"),