Fix -Wcast-qual warnings.

llvm-svn: 101786
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 035e57f..9cb27cc 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -718,7 +718,7 @@
 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD) {
   const ValueDecl *D = cast<ValueDecl>(GD.getDecl());
 
-  PrettyStackTraceDecl CrashInfo((ValueDecl *)D, D->getLocation(), 
+  PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(), 
                                  Context.getSourceManager(),
                                  "Generating code for declaration");