[C++] Rewrite of the preprocessor.

This rewrite fixes a couple of issues with the pre-processor. It now
supports:
- macros in macro bodies
- stringification of parameters [cpp.stringize]
- the concatenation operator [cpp.concat]
- #include MACRO_HERE
- defined() inside macro bodies used in pp-conditions.

Change-Id: Ifdb78041fb6afadf44f939a4bd66ce2832b8601f
Reviewed-by: Roberto Raggi <roberto.raggi@nokia.com>

src/libs/cplusplus/PPToken.cpp

@@ -0,0 +1,45 @@
+#include "PPToken.h"
+
+#include <cstring>
+
+using namespace CPlusPlus::Internal;
+
+ByteArrayRef::ByteArrayRef()
+    : m_ref(0)
+    , m_offset(0)
+    , m_length(0)
+{}
+
+bool ByteArrayRef::startsWith(const char *s) const
+{
+    int l = std::strlen(s);
+    if (l > m_length)
+        return false;
+    return !qstrncmp(start(), s, l);
+}
+
+int ByteArrayRef::count(char ch) const
+{
+    if (!m_ref)
+        return 0;
+
+    int num = 0;
+    const char *b = start();
+    const char *i = b + m_length;
+    while (i != b)
+        if (*--i == ch)
+            ++num;
+    return num;
+}
+
+PPToken::PPToken()
+{}
+
+void PPToken::squeeze()
+{
+    if (isValid()) {
+        m_src = m_src.mid(offset, length());
+        m_src.squeeze();
+        offset = 0;
+    }
+}