QmlProject: Add support for setting the environment

This allows setting arbitrary environment variables
in the .qmlproject.
This is required for example qtquickcontrols2.conf
and QT_AUTO_SCREEN_SCALE_FACTOR.

Task-number: QTCREATORBUG-19513
Change-Id: I8421a9fc7f85d24b3564f1b60f383be3838f2af4
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/qmlprojectmanager/qmlproject.cpp

@@ -213,6 +213,13 @@ Utils::FileName QmlProject::targetFile(const Utils::FileName &sourceFile,
     return Utils::FileName::fromString(QDir::cleanPath(targetDir.absoluteFilePath(relative)));
 }
 
+QList<Utils::EnvironmentItem> QmlProject::environment() const
+{
+    if (m_projectItem)
+        return m_projectItem.data()->environment();
+    return {};
+}
+
 bool QmlProject::validProjectFile() const
 {
     return !m_projectItem.isNull();