Fix error in the Win32 implementation pointed out by Howard Su.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74248 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Win32/ThreadLocal.inc b/lib/System/Win32/ThreadLocal.inc
index 0ba3be4..8ab37d9 100644
--- a/lib/System/Win32/ThreadLocal.inc
+++ b/lib/System/Win32/ThreadLocal.inc
@@ -42,7 +42,7 @@
 
 void ThreadLocalImpl::setInstance(const void* d){
   DWORD* tls = static_cast<DWORD*>(data);
-  int errorcode = TlsSetValue(*tls, d);
+  int errorcode = TlsSetValue(*tls, const_cast<void*>(d));
   assert(errorcode == 0);
 }