diff --git a/src/plugins/projectexplorer/gcctoolchain.cpp b/src/plugins/projectexplorer/gcctoolchain.cpp
index 9588d29ea51..c46ad267220 100644
--- a/src/plugins/projectexplorer/gcctoolchain.cpp
+++ b/src/plugins/projectexplorer/gcctoolchain.cpp
@@ -369,6 +369,7 @@ void GccToolChain::addToEnvironment(Utils::Environment &env) const
 {
     if (!m_compilerPath.isEmpty())
         env.prependOrSetPath(QFileInfo(m_compilerPath).absolutePath());
+    env.set(QLatin1String("LANG"), QLatin1String("C"));
 }
 
 void GccToolChain::setDebuggerCommand(const QString &d)