nixpkgs/pkgs/development/libraries/qt-5/5.8/qtdeclarative/nix-profiles-import-paths.patch

Index: qtdeclarative-opensource-src-5.8.0/src/qml/qml/qqmlimport.cpp
===================================================================
--- qtdeclarative-opensource-src-5.8.0.orig/src/qml/qml/qqmlimport.cpp
+++ qtdeclarative-opensource-src-5.8.0/src/qml/qml/qqmlimport.cpp
@@ -1630,6 +1630,15 @@ QQmlImportDatabase::QQmlImportDatabase(Q
     QString installImportsPath =  QLibraryInfo::location(QLibraryInfo::Qml2ImportsPath);
     addImportPath(installImportsPath);
 
+    // Add library paths derived from NIX_PROFILES.
+    const QStringList profiles = QFile::decodeName(qgetenv("NIX_PROFILES")).split(' ');
+    const QString qmldir = QStringLiteral(NIXPKGS_QML2_IMPORT_PREFIX);
+    for (const QString &profile: profiles) {
+        if (!profile.isEmpty()) {
+            addImportPath(profile + QDir::separator() + qmldir);
+        }
+    }
+
     // env import paths
     if (Q_UNLIKELY(!qEnvironmentVariableIsEmpty("QML2_IMPORT_PATH"))) {
         const QByteArray envImportPath = qgetenv("QML2_IMPORT_PATH");