ProjectExplorer: Introduce "extra data" handling for build system

That's meant to replace the per-ProjectNode storage, which cannot (or
is hard to be) used correctly for target/buildconfig/buildsystem
dependent data.

For now just redirect to the node storage to enable the users to
port to the new interface before finally changing the storage as such.

Change-Id: I14d30b4d68c93bac0f14b787e82d00d1e0ada3b2
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/projectexplorer/buildsystem.cpp

@@ -341,6 +341,20 @@ void BuildSystem::emitBuildSystemUpdated()
     target()->buildSystemUpdated(this);
 }
 
+void BuildSystem::setExtraData(const QString &buildKey, Core::Id dataKey, const QVariant &data)
+{
+    const ProjectNode *node = d->m_target->project()->findNodeForBuildKey(buildKey);
+    QTC_ASSERT(node, return);
+    node->setData(dataKey, data);
+}
+
+QVariant BuildSystem::extraData(const QString &buildKey, Core::Id dataKey) const
+{
+    const ProjectNode *node = d->m_target->project()->findNodeForBuildKey(buildKey);
+    QTC_ASSERT(node, return {});
+    return node->data(dataKey);
+}
+
 QString BuildSystem::disabledReason(const QString &buildKey) const
 {
     if (!hasParsingData()) {

src/plugins/projectexplorer/buildsystem.h

@@ -121,6 +121,9 @@ public:
 
     void emitBuildSystemUpdated();
 
+    void setExtraData(const QString &buildKey, Core::Id dataKey, const QVariant &data);
+    QVariant extraData(const QString &buildKey, Core::Id dataKey) const;
+
 public:
     // FIXME: Make this private and the BuildSystem a friend
     ParseGuard guardParsingRun() { return ParseGuard(this); }