Eliminate some VC++ warnings, patch by Hartmut Kaiser!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@41685 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Lex/LiteralSupport.cpp b/Lex/LiteralSupport.cpp
index 0428256..c2bdd8e 100644
--- a/Lex/LiteralSupport.cpp
+++ b/Lex/LiteralSupport.cpp
@@ -88,7 +88,7 @@
     for (; ThisTokBuf != ThisTokEnd; ++ThisTokBuf) {
       int CharVal = HexDigitValue(ThisTokBuf[0]);
       if (CharVal == -1) break;
-      Overflow |= ResultChar & 0xF0000000;  // About to shift out a digit?
+      Overflow |= (ResultChar & 0xF0000000) ? true : false;  // About to shift out a digit?
       ResultChar <<= 4;
       ResultChar |= CharVal;
     }