diff --git a/plugins/clang/duchain/duchainutils.cpp b/plugins/clang/duchain/duchainutils.cpp
index 4ffa51955a..61314d2580 100644
--- a/plugins/clang/duchain/duchainutils.cpp
+++ b/plugins/clang/duchain/duchainutils.cpp
@@ -1,112 +1,119 @@
 /*
  * Copyright 2014  Kevin Funk <kfunk@kde.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License or (at your option) version 3 or any later version
  * accepted by the membership of KDE e.V. (or its successor approved
  * by the membership of KDE e.V.), which shall act as a proxy
  * defined in Section 14 of version 3 of the license.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include "duchainutils.h"
 
 #include "util/clangdebug.h"
 
 #include <language/duchain/declaration.h>
 #include <language/duchain/duchainutils.h>
 #include <language/duchain/ducontext.h>
 #include <language/duchain/functiondefinition.h>
 #include <language/duchain/types/typeregister.h>
 
 #include "macrodefinition.h"
 #include "clangducontext.h"
 #include "clangparsingenvironmentfile.h"
 #include "types/classspecializationtype.h"
 
 #include "libclang_include_path.h"
 
 using namespace KDevelop;
 
 namespace ClangIntegration {
 
 KTextEditor::Range DUChainUtils::functionSignatureRange(const Declaration* decl)
 {
     if (!decl->isFunctionDeclaration()) {
         qCWarning(KDEV_CLANG) << "Invalid declaration:" << decl;
         return {};
     }
 
     auto functionContext = decl->internalContext();
     Q_ASSERT(functionContext);
     auto childContexts = functionContext->childContexts();
     if (childContexts.isEmpty()) {
         return functionContext->rangeInCurrentRevision();
     }
 
     const auto start = functionContext->rangeInCurrentRevision().start();
     const auto end = childContexts[0]->rangeInCurrentRevision().start();
     return {start, end};
 }
 
 void DUChainUtils::registerDUChainItems()
 {
     duchainRegisterType<ClangTopDUContext>();
     duchainRegisterType<ClangParsingEnvironmentFile>();
     duchainRegisterType<ClangNormalDUContext>();
     duchainRegisterType<MacroDefinition>();
 
     TypeSystem::self().registerTypeClass<ClassSpecializationType, ClassSpecializationTypeData>();
 }
 
 void DUChainUtils::unregisterDUChainItems()
 {
     TypeSystem::self().unregisterTypeClass<ClassSpecializationType, ClassSpecializationTypeData>();
 
     /// FIXME: this is currently not supported by the DUChain code...
     /// When the items are unregistered on plugin destruction, we'll get hit by
     /// assertions later on when the DUChain is finalized. There, when the data is getting cleaned up,
     /// we try to load all kinds of items again which would fail to find our items if we unregister.
     /// So let's not do it...
 /*
     duchainUnregisterType<ClangTopDUContext>();
     duchainUnregisterType<ClangParsingEnvironmentFile>();
     duchainUnregisterType<ClangNormalDUContext>();
     duchainUnregisterType<MacroDefinition>();
 
 */
 }
 
 ParseSessionData::Ptr DUChainUtils::findParseSessionData(const IndexedString &file, const IndexedString &tufile)
 {
     DUChainReadLocker lock;
     auto context = KDevelop::DUChainUtils::standardContextForUrl(file.toUrl());
     if (!context || !context->ast()) {
         // no cached data found for the current file, but maybe
         // we are lucky and can grab it from the TU context
         // this happens e.g. when originally a .cpp file is open and then one
         // of its included files is opened in the editor.
         context = KDevelop::DUChainUtils::standardContextForUrl(tufile.toUrl());
     }
 
     if (context) {
         return ParseSessionData::Ptr(dynamic_cast<ParseSessionData*>(context->ast().data()));
     }
     return {};
 }
 
 QString DUChainUtils::clangBuiltinIncludePath()
 {
-    return qEnvironmentVariable("KDEV_CLANG_BUILTIN_DIR", QStringLiteral(KDEV_CLANG_BUILTIN_DIR));
+    static const auto dir = []() -> QString {
+        auto dir = qgetenv("KDEV_CLANG_BUILTIN_DIR");
+        if (dir.isEmpty()) {
+            dir = KDEV_CLANG_BUILTIN_DIR;
+        }
+        return QString::fromUtf8(dir);
+    }();
+    return dir;
 }
 
 }