Fix -Wcast-qual warnings.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101786 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CodeGenAction.cpp b/lib/Frontend/CodeGenAction.cpp
index fdce211..80b0038 100644
--- a/lib/Frontend/CodeGenAction.cpp
+++ b/lib/Frontend/CodeGenAction.cpp
@@ -302,7 +302,7 @@
     BackendArgs.push_back("-time-passes");
   BackendArgs.push_back(0);
   llvm::cl::ParseCommandLineOptions(BackendArgs.size() - 1,
-                                    (char**) &BackendArgs[0]);
+                                    const_cast<char **>(&BackendArgs[0]));
 
   std::string FeaturesStr;
   if (TargetOpts.CPU.size() || TargetOpts.Features.size()) {