Fix -Wcast-qual warnings.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101786 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/driver/cc1_main.cpp b/tools/driver/cc1_main.cpp
index 41f2997..144a734 100644
--- a/tools/driver/cc1_main.cpp
+++ b/tools/driver/cc1_main.cpp
@@ -251,7 +251,7 @@
     for (unsigned i = 0; i != NumArgs; ++i)
       Args[i + 1] = Clang->getFrontendOpts().LLVMArgs[i].c_str();
     Args[NumArgs + 1] = 0;
-    llvm::cl::ParseCommandLineOptions(NumArgs + 1, (char**) Args);
+    llvm::cl::ParseCommandLineOptions(NumArgs + 1, const_cast<char **>(Args));
   }
 
   // Create the actual diagnostics engine.