revamp maintenance of base values (qmakespec+cache)

instantiate a complete evaluator instead of having just vars and
functions in the option object. that's cleaner.

Change-Id: I0ecd98307832ed072cebfd5b535572f7dcb103c1
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

src/shared/proparser/qmakeglobals.cpp

@@ -32,6 +32,7 @@
 
 #include "qmakeglobals.h"
 
+#include "qmakeevaluator.h"
 #include "ioutils.h"
 
 #include <QByteArray>
@@ -109,10 +110,12 @@ QMakeGlobals::QMakeGlobals()
 #ifdef PROEVALUATOR_THREAD_SAFE
     base_inProgress = false;
 #endif
+    base_eval = 0;
 }
 
 QMakeGlobals::~QMakeGlobals()
 {
+    delete base_eval;
 }
 
 void QMakeGlobals::setCommandLineArguments(const QStringList &args)