C++: Fix highlighting for lines with predefined macros

This adds definitions for the macros __FILE__, __LINE__, __DATE__ and
__TIME__ on demand.

As a side effect, this also introduces highlighting for the uses of
these macros.

Task-number: QTCREATORBUG-8036
Change-Id: Ib7546c7d45d2eecbc50c7883fc684e3497154405
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/cpptools/cppfindreferences.cpp

@@ -558,6 +558,8 @@ restart_search:
         usages.clear();
         foreach (const Document::MacroUse &use, doc->macroUses()) {
             const Macro &useMacro = use.macro();
+            if (useMacro.isPredefined())
+                continue;
 
             if (useMacro.fileName() == macro.fileName()) { // Check if this is a match, but possibly against an outdated document.
                 if (source.isEmpty())

src/plugins/cpptools/cpphighlightingsupportinternal.cpp

@@ -58,6 +58,9 @@ QFuture<TextEditor::HighlightingResult> CppHighlightingSupportInternal::highligh
 
     // Get macro definitions
     foreach (const CPlusPlus::Macro& macro, doc->definedMacros()) {
+        if (macro.isPredefined())
+            continue; // No "real" definition location
+
         int line, column;
         editor()->convertPosition(macro.offset(), &line, &column);
         ++column; //Highlighting starts at (column-1) --> compensate here