diff --git a/Utils.cpp b/Utils.cpp
index b96c8135..a8eb90fd 100644
--- a/Utils.cpp
+++ b/Utils.cpp
@@ -19,6 +19,8 @@
 
 using std::stringstream;
 
+bool CUtils::stdoutIsTTY;
+
 CUtils::CUtils() {}
 CUtils::~CUtils() {}