diff --git a/src/libs/utils/environment.cpp b/src/libs/utils/environment.cpp
index 0d312d8b8db..1aee1cf908e 100644
--- a/src/libs/utils/environment.cpp
+++ b/src/libs/utils/environment.cpp
@@ -454,13 +454,14 @@ FileName Environment::searchInPath(const QString &executable,
 
 QStringList Environment::path() const
 {
-    return m_values.value("PATH")
+    return value("PATH")
             .split(OsSpecificAspects(m_osType).pathListSeparator(), QString::SkipEmptyParts);
 }
 
 QString Environment::value(const QString &key) const
 {
-    return m_values.value(key);
+    const auto it = findKey(m_values, m_osType, key);
+    return it != m_values.end() ? it.value() : QString();
 }
 
 QString Environment::key(Environment::const_iterator it) const
diff --git a/src/plugins/clearcase/clearcaseplugin.h b/src/plugins/clearcase/clearcaseplugin.h
index 70c18334263..6aeacf68657 100644
--- a/src/plugins/clearcase/clearcaseplugin.h
+++ b/src/plugins/clearcase/clearcaseplugin.h
@@ -40,8 +40,6 @@
 
 QT_BEGIN_NAMESPACE
 class QAction;
-class QComboBox;
-class QDir;
 template <typename T>
 class QFutureInterface;
 class QMutex;
diff --git a/src/plugins/projectexplorer/project.h b/src/plugins/projectexplorer/project.h
index aac69ab22c8..9329fc3c437 100644
--- a/src/plugins/projectexplorer/project.h
+++ b/src/plugins/projectexplorer/project.h
@@ -169,8 +169,8 @@ public:
     bool isParsing() const;
     bool hasParsingData() const;
 
-    template<typename S, typename R, typename T>
-    void subscribeSignal(void (S::*sig)(), R*recv, T (R::*sl)()) {
+    template<typename S, typename R, typename T, typename ...Args1, typename ...Args2>
+    void subscribeSignal(void (S::*sig)(Args1...), R*recv, T (R::*sl)(Args2...)) {
         new Internal::ProjectSubscription([sig, recv, sl, this](ProjectConfiguration *pc) {
             if (S* sender = qobject_cast<S*>(pc))
                 return connect(sender, sig, recv, sl);
@@ -178,8 +178,8 @@ public:
         }, recv, this);
     }
 
-    template<typename S, typename R, typename T>
-    void subscribeSignal(void (S::*sig)(), R*recv, T sl) {
+    template<typename S, typename R, typename T, typename ...Args1>
+    void subscribeSignal(void (S::*sig)(Args1...), R*recv, T sl) {
         new Internal::ProjectSubscription([sig, recv, sl, this](ProjectConfiguration *pc) {
             if (S* sender = qobject_cast<S*>(pc))
                 return connect(sender, sig, recv, sl);
diff --git a/src/plugins/projectexplorer/projectmacro.h b/src/plugins/projectexplorer/projectmacro.h
index 9489b54d809..2a4537aaf89 100644
--- a/src/plugins/projectexplorer/projectmacro.h
+++ b/src/plugins/projectexplorer/projectmacro.h
@@ -87,7 +87,7 @@ private:
 inline
 uint qHash(const Macro &macro)
 {
-    using ::qHash;
+    using QT_PREPEND_NAMESPACE(qHash);
     return qHash(macro.key) ^ qHash(macro.value) ^ qHash(int(macro.type));
 }
 
diff --git a/src/plugins/vcsbase/vcsbaseclientsettings.cpp b/src/plugins/vcsbase/vcsbaseclientsettings.cpp
index f87daf18017..ab31348c1a1 100644
--- a/src/plugins/vcsbase/vcsbaseclientsettings.cpp
+++ b/src/plugins/vcsbase/vcsbaseclientsettings.cpp
@@ -363,7 +363,7 @@ Utils::FileName VcsBaseClientSettings::binaryPath() const
 
 QStringList VcsBaseClientSettings::searchPathList() const
 {
-    return stringValue(pathKey).split(Utils::HostOsInfo::pathListSeparator());
+    return stringValue(pathKey).split(Utils::HostOsInfo::pathListSeparator(), QString::SkipEmptyParts);
 }
 
 QString VcsBaseClientSettings::settingsGroup() const