Enhance data stored for macros and macro uses.

In preparation for finding macro uses.

* Macro: add offset and length
* MacroUse: add line
* Document: add convenience functions for finding a macro definition, use
  or undefined use at a given location.

Reviewed-by: Erik Verbruggen

src/plugins/cpptools/cppmodelmanager.cpp

@@ -455,7 +455,7 @@ void CppPreprocessor::passedMacroDefinitionCheck(unsigned offset, const Macro &m
     if (! m_currentDoc)
         return;
 
-    m_currentDoc->addMacroUse(macro, offset, macro.name().length(),
+    m_currentDoc->addMacroUse(macro, offset, macro.name().length(), env.currentLine,
                               QVector<MacroArgumentReference>(), true);
 }
 
@@ -477,7 +477,8 @@ void CppPreprocessor::startExpandingMacro(unsigned offset,
         return;
 
     //qDebug() << "start expanding:" << macro.name() << "text:" << originalText;
-    m_currentDoc->addMacroUse(macro, offset, originalText.length(), actuals, inCondition);
+    m_currentDoc->addMacroUse(macro, offset, originalText.length(), env.currentLine,
+                              actuals, inCondition);
 }
 
 void CppPreprocessor::stopExpandingMacro(unsigned, const Macro &)