Fixed stack-overflow when parsing insanely nested compound statements.

Thanks to Clang's parser_overflow.cpp which has >16000 nested compound
statements to check exactly the same.

Change-Id: I2b604f8ceb01115d7fe950994e0677a081e99481
Reviewed-by: Christian Kamm <christian.d.kamm@nokia.com>

src/libs/3rdparty/cplusplus/Parser.h

@@ -315,6 +315,7 @@ private:
     bool _inObjCImplementationContext: 1;
     bool _inExpressionStatement: 1;
     int _expressionDepth;
+    int _statementDepth;
 
     MemoryPool _expressionStatementTempPool;
     std::map<unsigned, TemplateArgumentListEntry> _templateArgumentList;