Qmake: Add special CONFIG variable "qtc_run" when parsing project files

The idea is that some of the more intrusive prf files in Qt can skip
themselves when they encounter this condition.

Task-number: QTCREATORBUG-17521
Change-Id: I09a33b2d3c5dee1232803d46c521cc9fd29e1898
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

src/plugins/qmakeprojectmanager/qmakeparsernodes.cpp

@@ -1246,6 +1246,7 @@ static bool evaluateOne(const QmakeEvalInput &input, ProFile *pro,
         QStringList basecfgs = reader->values(build + QLatin1String(".CONFIG"));
         basecfgs += build;
         basecfgs += QLatin1String("build_pass");
+        basecfgs += "qtc_run";
         basevars[QLatin1String("BUILD_PASS")] = QStringList(build);
         QStringList buildname = reader->values(build + QLatin1String(".name"));
         basevars[QLatin1String("BUILD_NAME")] = (buildname.isEmpty() ? QStringList(build) : buildname);

src/plugins/qtsupport/profilereader.cpp

@@ -79,6 +79,7 @@ ProFileReader::ProFileReader(QMakeGlobals *option, QMakeVfs *vfs)
     , ProFileEvaluator(option, this, vfs, this)
     , m_ignoreLevel(0)
 {
+    setExtraConfigs(QStringList("qtc_run"));
 }
 
 ProFileReader::~ProFileReader()