diff --git a/src/plugins/projectexplorer/gcctoolchain.cpp b/src/plugins/projectexplorer/gcctoolchain.cpp
index d593b8718c3..d36d9de74de 100644
--- a/src/plugins/projectexplorer/gcctoolchain.cpp
+++ b/src/plugins/projectexplorer/gcctoolchain.cpp
@@ -72,8 +72,7 @@ static QByteArray runGcc(const QString &gcc, const QStringList &arguments, const
     QProcess cpp;
     // Force locale: This function is used only to detect settings inside the tool chain, so this is save.
     QStringList environment(env);
-    environment.append(QLatin1String("LC_ALL"));
-    environment.append(QLatin1String("C"));
+    environment.append(QLatin1String("LC_ALL=C"));
 
     cpp.setEnvironment(environment);
     cpp.start(gcc, arguments);