Clang: Fix parsing MSVC's crtdefs.h for 64 Bit

...by specifying the word width, as for the Clang Static Analyzer.

This has gone unnoticed so far because it looks like that the error diagnostic
from the bug report can be extracted with libclang (as shown in the info bar),
but is not printed from libclang or clang.exe itself.

Task-number: QTCREATORBUG-17130
Change-Id: Ia7a5ee3825c7211cdf80c2166a9eb454ce48cac1
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/cpptools/compileroptionsbuilder.h

@@ -44,6 +44,7 @@ public:
     void addDefine(const QByteArray &defineDirective);
 
     // Add options based on project part
+    void addWordWidth();
     virtual void addTargetTriple();
     virtual void enableExceptions();
     void addHeaderPathOptions();